diff --git a/cui/source/dialogs/DiagramDialog.cxx b/cui/source/dialogs/DiagramDialog.cxx
index 5e7cebe37e8c..8cefc7c25842 100644
--- a/cui/source/dialogs/DiagramDialog.cxx
+++ b/cui/source/dialogs/DiagramDialog.cxx
@@ -69,30 +69,18 @@ IMPL_LINK_NOARG(DiagramDialog, OnAddClick, weld::Button&, void)
     if (pDiagramHelper && !sText.isEmpty())
     {
         SdrModel& rDrawModel(m_rDiagram.getSdrModelFromSdrObject());
-        const bool bUndo(rDrawModel.IsUndoEnabled());
-        svx::diagram::DiagramDataStatePtr aStartState;
+        OUString sNodeId = pDiagramHelper->addDiagramNode(sText, rDrawModel);
 
-        if (bUndo)
+        if (!sNodeId.isEmpty())
         {
-            // rescue all start state Diagram-defining data
-            aStartState = pDiagramHelper->extractDiagramDataState();
+            if (rDrawModel.IsUndoEnabled())
+                m_nUndos++;
+
+            std::unique_ptr<weld::TreeIter> pEntry(mpTreeDiagram->make_iterator());
+            mpTreeDiagram->insert(nullptr, -1, &sText, &sNodeId, nullptr, nullptr, false, pEntry.get());
+            mpTreeDiagram->select(*pEntry);
+            comphelper::dispatchCommand(u".uno:RegenerateDiagram"_ustr, {});
         }
-
-        OUString sNodeId = pDiagramHelper->addDiagramNode(sText);
-
-        if (bUndo)
-        {
-            // create undo action. That will internally secure the
-            // current Diagram-defining data as end state
-            rDrawModel.AddUndo(
-                rDrawModel.GetSdrUndoFactory().CreateUndoDiagramModelData(m_rDiagram, aStartState));
-            m_nUndos++;
-        }
-
-        std::unique_ptr<weld::TreeIter> pEntry(mpTreeDiagram->make_iterator());
-        mpTreeDiagram->insert(nullptr, -1, &sText, &sNodeId, nullptr, nullptr, false, pEntry.get());
-        mpTreeDiagram->select(*pEntry);
-        comphelper::dispatchCommand(u".uno:RegenerateDiagram"_ustr, {});
     }
 }
 
@@ -107,26 +95,10 @@ IMPL_LINK_NOARG(DiagramDialog, OnRemoveClick, weld::Button&, void)
     if (pDiagramHelper && pEntry)
     {
         SdrModel& rDrawModel(m_rDiagram.getSdrModelFromSdrObject());
-        const bool bUndo(rDrawModel.IsUndoEnabled());
-        svx::diagram::DiagramDataStatePtr aStartState;
-
-        if (bUndo)
+        if (pDiagramHelper->removeDiagramNode(mpTreeDiagram->get_id(*pEntry), rDrawModel))
         {
-            // rescue all start state Diagram-defining data
-            aStartState = pDiagramHelper->extractDiagramDataState();
-        }
-
-        if (pDiagramHelper->removeDiagramNode(mpTreeDiagram->get_id(*pEntry)))
-        {
-            if (bUndo)
-            {
-                // create undo action. That will internally secure the
-                // current Diagram-defining data as end state
-                rDrawModel.AddUndo(rDrawModel.GetSdrUndoFactory().CreateUndoDiagramModelData(
-                    m_rDiagram, aStartState));
+            if (rDrawModel.IsUndoEnabled())
                 m_nUndos++;
-            }
-
             mpTreeDiagram->remove(*pEntry);
             comphelper::dispatchCommand(u".uno:RegenerateDiagram"_ustr, {});
         }
diff --git a/include/oox/drawingml/diagram/diagramhelper_oox.hxx b/include/oox/drawingml/diagram/diagramhelper_oox.hxx
index 3c911981d473..7b1ff709fb51 100644
--- a/include/oox/drawingml/diagram/diagramhelper_oox.hxx
+++ b/include/oox/drawingml/diagram/diagramhelper_oox.hxx
@@ -83,9 +83,10 @@ public:
     virtual std::vector<std::pair<OUString, OUString>> getDiagramChildren(const OUString& rParentId) const override;
 
     // add/remove new top-level node to data model, returns its id
-    virtual OUString addDiagramNode(const OUString& rText) override;
-    virtual bool removeDiagramNode(const OUString& rNodeId) override;
+    virtual OUString addDiagramNode(const OUString& rText, SdrModel& rDrawModel) override;
+    virtual bool removeDiagramNode(const OUString& rNodeId, SdrModel& rDrawModel) override;
     virtual void TextInformationChange() override;
+    virtual void ItemSetInformationChange(std::span< const SfxPoolItem* const > aChangedItems) override;
 
     // Undo/Redo helpers to extract/restore Diagram-defining data
     virtual std::shared_ptr< svx::diagram::DiagramDataState > extractDiagramDataState() const override;
@@ -111,6 +112,8 @@ public:
 
     // write data to boost::property_tree
     virtual void addDiagramModelData(boost::property_tree::ptree& rTarget) const override;
+    virtual const OUString& getBackgroundShapeModelID() const override;
+    virtual bool isTextNodeModelID(const OUString& rModelID) const override;
 };
 
 class DiagramHelperFactory_oox : public svx::diagram::DiagramHelperFactory_svx
diff --git a/include/svx/diagram/DiagramHelper_svx.hxx b/include/svx/diagram/DiagramHelper_svx.hxx
index b1cf20441266..0bdc15fd5457 100644
--- a/include/svx/diagram/DiagramHelper_svx.hxx
+++ b/include/svx/diagram/DiagramHelper_svx.hxx
@@ -55,6 +55,8 @@ class DiagramDataState;
 class SVXCORE_DLLPUBLIC DiagramHelper_svx
 {
 private:
+    OUString msSelectedModelID;
+
     // These values define behaviour to where take data from at re-creation time.
     // Different definitions will have different consequences for re-creation
     // of Diagram visualization (if needed/triggered).
@@ -80,7 +82,14 @@ private:
     // a newly created oox::drawingml::Theme object
     bool mbForceThemePtrRecreation; // false
 
+    // flag to remember if locking of scale/translate was
+    // already done
+    bool mbDiagramObjectsLocked : 1;
+
 protected:
+    // helpers
+    void applyLocksToDiagramObjects(bool bActivate);
+
     // access associated SdrObjGroup/XShape/RootShape
     virtual css::uno::Reference< css::drawing::XShape >& accessRootShape() = 0;
 
@@ -105,9 +114,10 @@ public:
     getDiagramChildren(const OUString& rParentId) const = 0;
 
     // add/remove new top-level node to data model, returns its id
-    virtual OUString addDiagramNode(const OUString& rText) = 0;
-    virtual bool removeDiagramNode(const OUString& rNodeId) = 0;
+    virtual OUString addDiagramNode(const OUString& rText, SdrModel& rDrawModel) = 0;
+    virtual bool removeDiagramNode(const OUString& rNodeId, SdrModel& rDrawModel) = 0;
     virtual void TextInformationChange() = 0;
+    virtual void ItemSetInformationChange(std::span< const SfxPoolItem* const > aChangedItems) = 0;
 
     // Undo/Redo helpers for extracting/restoring Diagram-defining data
     virtual std::shared_ptr<svx::diagram::DiagramDataState> extractDiagramDataState() const = 0;
@@ -121,7 +131,7 @@ public:
     void connectToSdrObjGroup(const css::uno::Reference< css::drawing::XShape >& rTarget);
     void disconnectFromSdrObjGroup();
 
-    static void AddAdditionalVisualization(const SdrObjGroup& rTarget, SdrHdlList& rHdlList);
+    void AddAdditionalVisualization(SdrHdlList& rHdlList);
 
     // access to PropertyValues
     virtual css::uno::Any getOOXDomValue(svx::diagram::DomMapFlag aDomMapFlag) const = 0;
@@ -137,6 +147,18 @@ public:
 
     // write data to boost::property_tree
     virtual void addDiagramModelData(boost::property_tree::ptree& rTarget) const = 0;
+    virtual const OUString& getBackgroundShapeModelID() const = 0;
+    virtual bool isTextNodeModelID(const OUString& rModelID) const = 0;
+
+    const OUString& getSelectedModelID() const;
+    void setSelectedModelID(const OUString& rNew) { msSelectedModelID = rNew; }
+    SdrObject* getDiagramSubSelection();
+    void markDirectDiagramSubSelection(SdrObject& rCandidate);
+    bool markNextDiagramSubSelection(bool bPrev);
+    void initSelectionByKeyboard(bool bPrev);
+
+    // simple access to AssociatedRootShape
+    SdrObjGroup* getAssociatedRootShape();
 };
 
 class SVXCORE_DLLPUBLIC DiagramHelperFactory_svx
diff --git a/include/svx/diagram/datamodel_svx.hxx b/include/svx/diagram/datamodel_svx.hxx
index 85eed09b99ec..c96aae887b44 100644
--- a/include/svx/diagram/datamodel_svx.hxx
+++ b/include/svx/diagram/datamodel_svx.hxx
@@ -28,6 +28,7 @@
 
 #include <svx/svxdllapi.h>
 #include <svx/diagram/DomMapFlag.hxx>
+#include <basegfx/matrix/b2dhommatrix.hxx>
 #include <rtl/ustring.hxx>
 #include <rtl/ustrbuf.hxx>
 
@@ -150,12 +151,16 @@ class UNLESS_MERGELIBS(SVXCORE_DLLPUBLIC) DiagramDataState
 {
     Connections maConnections;
     Points maPoints;
+    std::vector<css::uno::Reference<css::drawing::XShape>> mxShapes;
+    basegfx::B2DHomMatrix maTransformation;
 
 public:
-    DiagramDataState(Connections aConnections, Points aPoints);
+    DiagramDataState(const Connections& aConnections, const Points& aPoints, const css::uno::Reference< css::drawing::XShape >& rRootShape);
 
-    Connections& getConnections() { return maConnections; }
-    Points& getPoints() { return maPoints; }
+    const Connections& getConnections() const { return maConnections; }
+    const Points& getPoints() const { return maPoints; }
+    const std::vector<css::uno::Reference<css::drawing::XShape>>& getXShapes() const { return mxShapes;}
+    const basegfx::B2DHomMatrix& getTransformation() const { return maTransformation; }
 };
 
 typedef std::shared_ptr< DiagramDataState > DiagramDataStatePtr;
diff --git a/include/svx/svdobj.hxx b/include/svx/svdobj.hxx
index 60dc4040dbeb..890052069575 100644
--- a/include/svx/svdobj.hxx
+++ b/include/svx/svdobj.hxx
@@ -228,10 +228,14 @@ public:
     // Basic DiagramHelper support
     virtual bool isDiagram() const;
     virtual const std::shared_ptr< svx::diagram::DiagramHelper_svx >& getDiagramHelper() const;
-    const std::shared_ptr< svx::diagram::DiagramHelper_svx >& getDiagramHelperFromDiagramOrMember() const;
     void setDiagramDataModelID(const OUString& rID);
     const OUString& getDiagramDataModelID() const;
 
+    virtual SdrObject* getDiagramSubSelection();
+    bool isDiagramBackgroundShape() const;
+    bool isDiagramTextNode() const;
+    bool removeDiagramNode();
+
 private:
     // check if a ObjectName is set and it is in DiagramModelID syntax
     bool ObjectNameIsDiagramModelID();
diff --git a/include/svx/svdogrp.hxx b/include/svx/svdogrp.hxx
index e5e24770d2db..2f8977c0eadd 100644
--- a/include/svx/svdogrp.hxx
+++ b/include/svx/svdogrp.hxx
@@ -31,6 +31,7 @@ public:
     // Basic DiagramHelper support
     virtual bool isDiagram() const override;
     virtual const std::shared_ptr< svx::diagram::DiagramHelper_svx >& getDiagramHelper() const override;
+    virtual SdrObject* getDiagramSubSelection() override;
 
 private:
     virtual std::unique_ptr<sdr::contact::ViewContact> CreateObjectSpecificViewContact() override;
diff --git a/include/svx/svdundo.hxx b/include/svx/svdundo.hxx
index bb83dc944c15..53fdfdbf6419 100644
--- a/include/svx/svdundo.hxx
+++ b/include/svx/svdundo.hxx
@@ -233,8 +233,6 @@ class UNLESS_MERGELIBS(SVXCORE_DLLPUBLIC) SdrUndoDiagramModelData final : public
     std::shared_ptr< svx::diagram::DiagramDataState > m_aStartState;
     std::shared_ptr< svx::diagram::DiagramDataState > m_aEndState;
 
-    void implUndoRedo(bool bUndo);
-
 public:
     SdrUndoDiagramModelData(SdrObject& rNewObj, const std::shared_ptr< svx::diagram::DiagramDataState >& rStartState);
     virtual ~SdrUndoDiagramModelData() override;
diff --git a/oox/source/drawingml/diagram/diagram.cxx b/oox/source/drawingml/diagram/diagram.cxx
index 05700c83112d..3b01c15244e2 100644
--- a/oox/source/drawingml/diagram/diagram.cxx
+++ b/oox/source/drawingml/diagram/diagram.cxx
@@ -121,7 +121,6 @@ static void removeUnneededGroupShapes(const ShapePtr& pShape)
     }
 }
 
-
 void SmartArtDiagram::createShapeHierarchyFromModel( const ShapePtr & pParentShape, bool bCreate )
 {
     if (pParentShape->getSize().Width == 0 || pParentShape->getSize().Height == 0)
@@ -152,11 +151,6 @@ void SmartArtDiagram::createShapeHierarchyFromModel( const ShapePtr & pParentSha
     pBackground->setSize(pParentShape->getSize());
     if (mpData->getBackgroundShapeFillProperties())
         pBackground->getFillProperties() = *mpData->getBackgroundShapeFillProperties();
-    // MoveProtect/SizeProtect..? Keep for now, but may be removed
-    // when IA needs change - the Diagram will be a closed GroupObject.
-    // If it gets 'broken' (un-grouped) the BGShape will keep that attributes,
-    // despite main reason to break that Diagram is probably to edit it.
-    pBackground->setLocked(true);
 
     // create and set ModelID for BackgroundShape to allow later association
     getData()->setBackgroundShapeModelID(OStringToOUString(comphelper::xml::generateGUIDString(), RTL_TEXTENCODING_UTF8));
@@ -166,10 +160,26 @@ void SmartArtDiagram::createShapeHierarchyFromModel( const ShapePtr & pParentSha
     aChildren.insert(aChildren.begin(), pBackground);
 }
 
+uno::Reference<xml::dom::XDocument> SmartArtDiagram::convertAndSet(std::u16string_view rDOM, svx::diagram::DomMapFlag aDomMapFlag)
+{
+    // construct MemoryStream and OStreamWrapper
+    const OString sUtf8(OUStringToOString(rDOM, RTL_TEXTENCODING_UTF8));
+    SvMemoryStream aStream(const_cast<char*>(sUtf8.getStr()), sUtf8.getLength(), StreamMode::READ);
+    rtl::Reference<utl::OStreamWrapper> pStreamWrapper = new utl::OStreamWrapper(aStream);
+
+    // create the dom parser & create DomTree
+    uno::Reference<xml::dom::XDocumentBuilder> xDomBuilder(xml::dom::DocumentBuilder::create(comphelper::getProcessComponentContext()));
+    uno::Reference<xml::dom::XDocument> aDomTree(xDomBuilder->parse(pStreamWrapper->getInputStream()));
+
+    // set DomTree locally
+    setOOXDomValue(aDomMapFlag, uno::Any(aDomTree));
+    return aDomTree;
+}
+
 SmartArtDiagram::SmartArtDiagram()
 : maDiagramFontHeights()
-, mpData()
-, mpLayout()
+, mpData(std::make_shared<DiagramData_oox>())
+, mpLayout(std::make_shared<DiagramLayout>(*this))
 , maStyles()
 , maColors()
 , maDiagramPRDomMap()
@@ -209,67 +219,33 @@ SmartArtDiagram::SmartArtDiagram(const boost::property_tree::ptree& rDiagramMode
 
         if (!aOOXLayoutDOM.isEmpty())
         {
-            // construct MemoryStream and OStreamWrapper with SVG in OUString
-            const OString sUtf8(OUStringToOString(aOOXLayoutDOM, RTL_TEXTENCODING_UTF8));
-            SvMemoryStream aStream(const_cast<char*>(sUtf8.getStr()), sUtf8.getLength(), StreamMode::READ);
-            rtl::Reference<utl::OStreamWrapper> pStreamWrapper = new utl::OStreamWrapper(aStream);
-
-            // create the dom parser & create DomTree
-            uno::Reference<xml::dom::XDocumentBuilder> xDomBuilder(xml::dom::DocumentBuilder::create(comphelper::getProcessComponentContext()));
-            uno::Reference<xml::dom::XDocument> aDomTree(xDomBuilder->parse(pStreamWrapper->getInputStream()));
-
-            // set DomTree locally
-            setOOXDomValue(svx::diagram::DomMapFlag::OOXLayout, uno::Any(aDomTree));
+            // create and set DomTree locally
+            uno::Reference<xml::dom::XDocument> xDom(convertAndSet(aOOXLayoutDOM, svx::diagram::DomMapFlag::OOXLayout));
 
             // import DomTree to mpLayout
-            uno::Reference<xml::sax::XFastSAXSerializable> xSerializer(aDomTree, uno::UNO_QUERY_THROW);
+            uno::Reference<xml::sax::XFastSAXSerializable> xSerializer(xDom, uno::UNO_QUERY_THROW);
             rtl::Reference< core::FragmentHandler > xRefLayout(new DiagramLayoutFragmentHandler(*this, *xPPTImport, "internal", mpLayout));
             xPPTImport->importFragment(xRefLayout, xSerializer);
-
-            // Data is loaded, so we already have Points and Connections. Also
-            // need to rebuild buffers for layouting (maPointsPresNameMap,
-            // maConnectionNameMap, maPresOfNameMap). Call with false due to
-            // we are in ODF import and have no oox::Shapes to delete and do
-            // *not* want these to be created (would not hurt, but not needed)
-            // getData()->buildDiagramDataModel(false);
         }
 
         if (!aOOXStyleDOM.isEmpty())
         {
-            // construct MemoryStream and OStreamWrapper with SVG in OUString
-            const OString sUtf8(OUStringToOString(aOOXStyleDOM, RTL_TEXTENCODING_UTF8));
-            SvMemoryStream aStream(const_cast<char*>(sUtf8.getStr()), sUtf8.getLength(), StreamMode::READ);
-            rtl::Reference<utl::OStreamWrapper> pStreamWrapper = new utl::OStreamWrapper(aStream);
-
-            // create the dom parser & create DomTree
-            uno::Reference<xml::dom::XDocumentBuilder> xDomBuilder(xml::dom::DocumentBuilder::create(comphelper::getProcessComponentContext()));
-            uno::Reference<xml::dom::XDocument> aDomTree(xDomBuilder->parse(pStreamWrapper->getInputStream()));
-
-            // set DomTree locally
-            setOOXDomValue(svx::diagram::DomMapFlag::OOXStyle, uno::Any(aDomTree));
+            // create and set DomTree locally
+            uno::Reference<xml::dom::XDocument> xDom(convertAndSet(aOOXStyleDOM, svx::diagram::DomMapFlag::OOXStyle));
 
             // import DomTree to maStyles
-            uno::Reference<xml::sax::XFastSAXSerializable> xSerializer(aDomTree, uno::UNO_QUERY_THROW);
+            uno::Reference<xml::sax::XFastSAXSerializable> xSerializer(xDom, uno::UNO_QUERY_THROW);
             rtl::Reference< core::FragmentHandler > xRefLayout(new DiagramQStylesFragmentHandler(*xPPTImport, "internal", maStyles));
             xPPTImport->importFragment(xRefLayout, xSerializer);
         }
 
         if (!aOOXColorDOM.isEmpty())
         {
-            // construct MemoryStream and OStreamWrapper with SVG in OUString
-            const OString sUtf8(OUStringToOString(aOOXColorDOM, RTL_TEXTENCODING_UTF8));
-            SvMemoryStream aStream(const_cast<char*>(sUtf8.getStr()), sUtf8.getLength(), StreamMode::READ);
-            rtl::Reference<utl::OStreamWrapper> pStreamWrapper = new utl::OStreamWrapper(aStream);
-
-            // create the dom parser & create DomTree
-            uno::Reference<xml::dom::XDocumentBuilder> xDomBuilder(xml::dom::DocumentBuilder::create(comphelper::getProcessComponentContext()));
-            uno::Reference<xml::dom::XDocument> aDomTree(xDomBuilder->parse(pStreamWrapper->getInputStream()));
-
-            // set DomTree locally
-            setOOXDomValue(svx::diagram::DomMapFlag::OOXColor, uno::Any(aDomTree));
+            // create and set DomTree locally
+            uno::Reference<xml::dom::XDocument> xDom(convertAndSet(aOOXColorDOM, svx::diagram::DomMapFlag::OOXColor));
 
             // import DomTree to maColors
-            uno::Reference<xml::sax::XFastSAXSerializable> xSerializer(aDomTree, uno::UNO_QUERY_THROW);
+            uno::Reference<xml::sax::XFastSAXSerializable> xSerializer(xDom, uno::UNO_QUERY_THROW);
             rtl::Reference< core::FragmentHandler > xRefLayout(new ColorFragmentHandler(*xPPTImport, "internal", maColors));
             xPPTImport->importFragment(xRefLayout, xSerializer);
         }
@@ -598,12 +574,6 @@ void loadDiagram( ShapePtr const & pShape,
 {
     DiagramPtr pDiagram = std::make_shared<SmartArtDiagram>();
 
-    OoxDiagramDataPtr pData = std::make_shared<DiagramData_oox>();
-    pDiagram->setData( pData );
-
-    DiagramLayoutPtr pLayout = std::make_shared<DiagramLayout>(*pDiagram);
-    pDiagram->setLayout( pLayout );
-
     try
     {
         // set DiagramFontHeights at filter
@@ -613,7 +583,7 @@ void loadDiagram( ShapePtr const & pShape,
         if( !rDataModelPath.isEmpty() )
         {
             rtl::Reference< core::FragmentHandler > xRefDataModel(
-                    new DiagramDataFragmentHandler( rFilter, rDataModelPath, pData ));
+                    new DiagramDataFragmentHandler( rFilter, rDataModelPath, pDiagram->getData() ));
 
             importFragment(rFilter,
                            loadFragment(rFilter,xRefDataModel),
@@ -634,7 +604,7 @@ void loadDiagram( ShapePtr const & pShape,
                                      uno::Any(aDataHlinkRelsMap));
 
             // Pass the info to pShape
-            for (auto const& extDrawing : pData->getExtDrawings())
+            for (auto const& extDrawing : pDiagram->getData()->getExtDrawings())
             {
                 OUString aFragmentPath = rRelations.getFragmentPathFromRelId(extDrawing);
                 // Ignore RelIds which don't resolve to a fragment path.
@@ -665,8 +635,7 @@ void loadDiagram( ShapePtr const & pShape,
         if (!rLayoutPath.isEmpty())
         {
             rtl::Reference< core::FragmentHandler > xRefLayout(
-                    new DiagramLayoutFragmentHandler( *pDiagram, rFilter, rLayoutPath,
-                                                      std::move(pLayout) ));
+                    new DiagramLayoutFragmentHandler( *pDiagram, rFilter, rLayoutPath, pDiagram->getLayout()));
 
             importFragment(rFilter,
                     loadFragment(rFilter,xRefLayout),
@@ -701,7 +670,7 @@ void loadDiagram( ShapePtr const & pShape,
                 xRefColorStyle);
         }
 
-        if( !pData->getExtDrawings().empty() )
+        if( !pDiagram->getData()->getExtDrawings().empty() )
         {
             const DiagramColorMap::const_iterator aColor = pDiagram->getColors().find(u"node0"_ustr);
             if( aColor != pDiagram->getColors().end() && !aColor->second.maTextFillColors.empty())
@@ -714,9 +683,9 @@ void loadDiagram( ShapePtr const & pShape,
 
         // collect data, init maps
         // for Diagram import, do - for now - NOT clear all oox::drawingml::Shape
-        pData->buildDiagramDataModel(false);
+        pDiagram->getData()->buildDiagramDataModel(false);
 #ifdef DBG_UTIL
-        pData->dump();
+        pDiagram->getData()->dump();
 #endif
 
         // diagram loaded. now lump together & attach to shape
@@ -735,9 +704,11 @@ void loadDiagram( ShapePtr const & pShape,
         // original ImportData directly to the Diagram ModelData
         std::shared_ptr<::oox::drawingml::Theme> aTheme(rFilter.getCurrentThemePtr());
         if(aTheme)
-            pData->setThemeDocument(aTheme->getFragment()); //getTempFile());
+            pDiagram->getData()->setThemeDocument(aTheme->getFragment());
 
         // Prepare support for the advanced DiagramHelper using Diagram & Theme data
+        // This is where pDiagram is moved to where it will stay, else it wil get
+        // cleaned up (what is intended)
         pShape->prepareDiagramHelper(pDiagram, rFilter.getCurrentThemePtr());
     }
     catch (...)
diff --git a/oox/source/drawingml/diagram/diagram.hxx b/oox/source/drawingml/diagram/diagram.hxx
index 327787d9f0b5..51bd73fa6067 100644
--- a/oox/source/drawingml/diagram/diagram.hxx
+++ b/oox/source/drawingml/diagram/diagram.hxx
@@ -132,14 +132,8 @@ public:
     explicit SmartArtDiagram(SmartArtDiagram const& rSource);
     explicit SmartArtDiagram(const boost::property_tree::ptree& rDiagramModel);
     ~SmartArtDiagram();
-    void setData( const OoxDiagramDataPtr& pData )
-        { mpData = pData; }
-    const OoxDiagramDataPtr& getData() const
-        { return mpData; }
-    void setLayout( const DiagramLayoutPtr & pLayout )
-        { mpLayout = pLayout; }
-    const DiagramLayoutPtr& getLayout() const
-        { return mpLayout; }
+    const OoxDiagramDataPtr& getData() const { return mpData; }
+    const DiagramLayoutPtr& getLayout() const { return mpLayout; }
 
     DiagramQStyleMap& getStyles() { return maStyles; }
     const DiagramQStyleMap& getStyles() const { return maStyles; }
@@ -165,8 +159,9 @@ public:
     void addDiagramModelData(boost::property_tree::ptree& rTarget) const;
 
 private:
-    // helper for addDiagramModelData
+    // helpers
     void addDomTreeToModelData(svx::diagram::DomMapFlag aId, std::u16string_view aName, boost::property_tree::ptree& rTarget) const;
+    css::uno::Reference<css::xml::dom::XDocument> convertAndSet(std::u16string_view rDOM, svx::diagram::DomMapFlag aDomMapFlag);
 
     // This contains groups of shapes: automatic font size is the same in each group.
     oox::core::NamedShapePairs maDiagramFontHeights;
diff --git a/oox/source/drawingml/diagram/diagramhelper_oox.cxx b/oox/source/drawingml/diagram/diagramhelper_oox.cxx
index 479e5472db73..61db150f97ca 100644
--- a/oox/source/drawingml/diagram/diagramhelper_oox.cxx
+++ b/oox/source/drawingml/diagram/diagramhelper_oox.cxx
@@ -28,6 +28,7 @@
 #include <svx/svdoutl.hxx>
 #include <svx/svditer.hxx>
 #include <svx/diagram/DomMapFlag.hxx>
+#include <svx/svdundo.hxx>
 #include <comphelper/processfactory.hxx>
 #include <oox/drawingml/themefragmenthandler.hxx>
 #include <com/sun/star/xml/sax/XFastSAXSerializable.hpp>
@@ -224,6 +225,11 @@ void DiagramHelper_oox::reLayout()
     // Re-apply remembered geometry
     pTarget->TRSetBaseGeometry(aTransformation, aPolyPolygon);
 
+    // new SdrObjects created, re-apply geometry change locks as needed
+    // and reset SubSelection
+    applyLocksToDiagramObjects(true);
+    setSelectedModelID(EMPTY_OUSTRING);
+
     // extract newly created DrawingLayerModelData
     std::vector<uno::Reference<drawing::XShape>> xNewXShapes;
     uno::Reference<drawing::XShape> xNewShape;
@@ -335,70 +341,137 @@ DiagramHelper_oox::getDiagramChildren(const OUString& rParentId) const
     return std::vector<std::pair<OUString, OUString>>();
 }
 
-OUString DiagramHelper_oox::addDiagramNode(const OUString& rText)
+OUString DiagramHelper_oox::addDiagramNode(const OUString& rText, SdrModel& rDrawModel)
 {
     OUString aRetval;
 
     if (hasDiagramData())
     {
+        const bool bUndo(rDrawModel.IsUndoEnabled());
+        svx::diagram::DiagramDataStatePtr aStartState;
+
+        if (bUndo)
+        {
+            // rescue all start state Diagram-defining data
+            aStartState = extractDiagramDataState();
+        }
+
         const std::pair<OUString, DomMapFlags> aResult = mpDiagramPtr->getData()->addDiagramNode();
         aRetval = aResult.first;
 
-        // reset Dom properties at DiagramData
-        mpDiagramPtr->resetOOXDomValues(aResult.second);
-
-        // reset temporary buffered ModelData association lists & rebuild them
-        // and the Diagram DataModel
-        mpDiagramPtr->getData()->buildDiagramDataModel(true);
-
-        // also reset temporary buffered layout data - that might
-        // still refer to changed oox::Shape data
-        mpDiagramPtr->getLayout()->getPresPointShapeMap().clear();
-
-        // we have the text node in aRetval, but we need the ModelID
-        // of the node referring that one, that is the one that will be used
-        // as ModelID in the XShape/SdrObject. Loop and look for it
-        for (const auto& rCandidate : mpDiagramPtr->getData()->getPoints())
+        if (!aRetval.isEmpty())
         {
-            if (!rCandidate.msPresentationAssociationId.isEmpty()
-                && rCandidate.msPresentationAssociationId == aRetval)
+            // reset Dom properties at DiagramData
+            mpDiagramPtr->resetOOXDomValues(aResult.second);
+
+            // reset temporary buffered ModelData association lists & rebuild them
+            // and the Diagram DataModel
+            mpDiagramPtr->getData()->buildDiagramDataModel(true);
+
+            // also reset temporary buffered layout data - that might
+            // still refer to changed oox::Shape data
+            mpDiagramPtr->getLayout()->getPresPointShapeMap().clear();
+
+            // we have the text node in aRetval, but we need the ModelID
+            // of the node referring that one, that is the one that will be used
+            // as ModelID in the XShape/SdrObject. Loop and look for it
+            for (const auto& rCandidate : mpDiagramPtr->getData()->getPoints())
             {
-                msNewNodeId = rCandidate.msModelId;
-                break;
+                if (!rCandidate.msPresentationAssociationId.isEmpty()
+                    && rCandidate.msPresentationAssociationId == aRetval)
+                {
+                    msNewNodeId = rCandidate.msModelId;
+                    break;
+                }
+            }
+
+            msNewNodeText = rText;
+
+            if (bUndo)
+            {
+                // create undo action. That will internally secure the
+                // current Diagram-defining data as end state
+                SdrObject* pRootShape(SdrObject::getSdrObjectFromXShape(accessRootShape()));
+                assert(nullptr != pRootShape && "Missing RootShape in DiagramHelper_oox (!)");
+                rDrawModel.AddUndo(rDrawModel.GetSdrUndoFactory().CreateUndoDiagramModelData(
+                    *pRootShape, aStartState));
             }
         }
-
-        // msNewNodeId = aRetval;
-        msNewNodeText = rText;
     }
 
     return aRetval;
 }
 
-bool DiagramHelper_oox::removeDiagramNode(const OUString& rNodeId)
+bool DiagramHelper_oox::removeDiagramNode(const OUString& rNodeId, SdrModel& rDrawModel)
 {
     bool bRetval(false);
 
     if (hasDiagramData())
     {
-        DomMapFlags aResult = mpDiagramPtr->getData()->removeDiagramNode(rNodeId);
-        bRetval = !aResult.empty();
+        const bool bUndo(rDrawModel.IsUndoEnabled());
+        svx::diagram::DiagramDataStatePtr aStartState;
 
-        // reset Dom properties at DiagramData
-        mpDiagramPtr->resetOOXDomValues(std::move(aResult));
+        if (bUndo)
+        {
+            // rescue all start state Diagram-defining data
+            aStartState = extractDiagramDataState();
+        }
 
-        // reset temporary buffered ModelData association lists & rebuild them
-        // and the Diagram DataModel
-        mpDiagramPtr->getData()->buildDiagramDataModel(true);
+        DomMapFlags aResult(mpDiagramPtr->getData()->removeDiagramNode(rNodeId));
 
-        // also reset temporary buffered layout data - that might
-        // still refer to changed oox::Shape data
-        mpDiagramPtr->getLayout()->getPresPointShapeMap().clear();
+        if (!aResult.empty())
+        {
+            bRetval = true;
+
+            // reset Dom properties at DiagramData
+            mpDiagramPtr->resetOOXDomValues(std::move(aResult));
+
+            // reset temporary buffered ModelData association lists & rebuild them
+            // and the Diagram DataModel
+            mpDiagramPtr->getData()->buildDiagramDataModel(true);
+
+            // also reset temporary buffered layout data - that might
+            // still refer to changed oox::Shape data
+            mpDiagramPtr->getLayout()->getPresPointShapeMap().clear();
+
+            if (bUndo)
+            {
+                // create undo action. That will internally secure the
+                // current Diagram-defining data as end state
+                SdrObject* pRootShape(SdrObject::getSdrObjectFromXShape(accessRootShape()));
+                assert(nullptr != pRootShape && "Missing RootShape in DiagramHelper_oox (!)");
+                rDrawModel.AddUndo(rDrawModel.GetSdrUndoFactory().CreateUndoDiagramModelData(
+                    *pRootShape, aStartState));
+            }
+        }
     }
 
     return bRetval;
 }
 
+void DiagramHelper_oox::ItemSetInformationChange(std::span<const SfxPoolItem* const> aChangedItems)
+{
+    bool bFillChanged(false);
+    bool bLineChanged(false);
+    bool bTextChanged(false);
+
+    for (const SfxPoolItem* pItem : aChangedItems)
+    {
+        bFillChanged |= (pItem->Which() >= XATTR_FILL_FIRST && pItem->Which() <= XATTR_FILL_LAST);
+        bLineChanged |= (pItem->Which() >= XATTR_LINE_FIRST && pItem->Which() <= XATTR_LINE_LAST);
+        bTextChanged |= (pItem->Which() >= XATTR_TEXT_FIRST && pItem->Which() <= XATTR_TEXT_LAST);
+    }
+
+    if (bFillChanged || bLineChanged || bTextChanged)
+    {
+        // attributes of one of the contained shapes have
+        // changed. Maybe other actions are needed in the
+        // future, but for now do general reset like
+        // TextInformationChange() does
+        TextInformationChange();
+    }
+}
+
 void DiagramHelper_oox::TextInformationChange()
 {
     if (!mpDiagramPtr)
@@ -543,6 +616,29 @@ void DiagramHelper_oox::addDiagramModelData(boost::property_tree::ptree& rTarget
     mpDiagramPtr->addDiagramModelData(rTarget);
 }
 
+const OUString& DiagramHelper_oox::getBackgroundShapeModelID() const
+{
+    if (!mpDiagramPtr)
+        return EMPTY_OUSTRING;
+
+    return mpDiagramPtr->getData()->getBackgroundShapeModelID();
+}
+
+bool DiagramHelper_oox::isTextNodeModelID(const OUString& rModelID) const
+{
+    if (!mpDiagramPtr || rModelID.isEmpty())
+        return false;
+
+    for (const auto& rCandidate : mpDiagramPtr->getData()->getPoints())
+    {
+        if (rCandidate.msModelId == rModelID
+            && rCandidate.msPresentationLayoutName == u"textNode"_ustr)
+            return true;
+    }
+
+    return false;
+}
+
 DiagramHelperFactory_oox::DiagramHelperFactory_oox()
     : DiagramHelperFactory_svx()
 {
diff --git a/oox/source/export/drawingml.cxx b/oox/source/export/drawingml.cxx
index 473e1f7b6c45..78842f2f0e6f 100644
--- a/oox/source/export/drawingml.cxx
+++ b/oox/source/export/drawingml.cxx
@@ -2326,7 +2326,7 @@ void DrawingML::WriteShapeTransformation( const Reference< XShape >& rXShape, sa
 
         if (nullptr != pShape)
         {
-            std::shared_ptr< svx::diagram::DiagramHelper_svx > pDiagramHelper(pShape->getDiagramHelperFromDiagramOrMember());
+            std::shared_ptr< svx::diagram::DiagramHelper_svx > pDiagramHelper(pShape->getDiagramHelper());
 
             if (pDiagramHelper)
             {
diff --git a/sc/source/ui/drawfunc/fusel.cxx b/sc/source/ui/drawfunc/fusel.cxx
index 5b0b7188608e..e0cce98850e2 100644
--- a/sc/source/ui/drawfunc/fusel.cxx
+++ b/sc/source/ui/drawfunc/fusel.cxx
@@ -27,6 +27,7 @@
 #include <svx/svdomedia.hxx>
 #include <svx/svdpagv.hxx>
 #include <svx/ImageMapInfo.hxx>
+#include <svx/diagram/DiagramHelper_svx.hxx>
 #include <editeng/outlobj.hxx>
 #include <sfx2/app.hxx>
 #include <sfx2/ipclient.hxx>
@@ -359,6 +360,7 @@ bool FuSelection::MouseButtonUp(const MouseEvent& rMEvt)
     SdrPage* pPage = ( pPageView ? pPageView->GetPage() : nullptr );
     ::std::vector< OUString > aExcludedChartNames;
     ScRangeListVector aProtectedChartRangesVector;
+    bool bWasDragged = false;
 
     if (comphelper::LibreOfficeKit::isActive() && rDocument.IsNegativePage(rViewData.CurrentTabForData()))
         aPnt.setX(-aPnt.X());
@@ -406,7 +408,7 @@ bool FuSelection::MouseButtonUp(const MouseEvent& rMEvt)
                     return true;
                 }
             }
-            pView->EndDragObj( rMEvt.IsMod1() );
+            bWasDragged = pView->EndDragObj( rMEvt.IsMod1() );
             pView->ForceMarkedToAnotherPage();
 
             bReturn = true;
@@ -529,6 +531,32 @@ bool FuSelection::MouseButtonUp(const MouseEvent& rMEvt)
             bReturn = true;
     }
 
+    if (!bWasDragged)
+    {
+        const SdrMarkList& rMarkList(pView->GetMarkedObjectList());
+        if (rMarkList.GetMarkCount() == 1)
+        {
+            SdrObject* pSingleObj = rMarkList.GetMark(0)->GetMarkedSdrObj();
+
+            if(nullptr != pSingleObj && pSingleObj->isDiagram())
+            {
+                const std::shared_ptr< svx::diagram::DiagramHelper_svx >& rDiagramHelper(pSingleObj->getDiagramHelper());
+                if (rDiagramHelper)
+                {
+                    SdrPageView* pPV;
+                    SdrObject* pCandidate = pView->PickObj(aMDPos, pView->getHitTolLog(), pPV, SdrSearchOptions::DEEP);
+                    if (pCandidate && !pCandidate->isDiagram())
+                    {
+                        rDiagramHelper->markDirectDiagramSubSelection(*pCandidate);
+                        pView->UnmarkAllObj();
+                        pView->MarkObj(pSingleObj,pPV);
+                        return true;
+                    }
+                }
+            }
+        }
+    }
+
     ForcePointer(&rMEvt);
 
     if (pWindow->IsMouseCaptured())
diff --git a/sd/qa/unit/tiledrendering/tiledrendering.cxx b/sd/qa/unit/tiledrendering/tiledrendering.cxx
index a0fc63542e0a..038903eebe60 100644
--- a/sd/qa/unit/tiledrendering/tiledrendering.cxx
+++ b/sd/qa/unit/tiledrendering/tiledrendering.cxx
@@ -2273,6 +2273,12 @@ CPPUNIT_TEST_FIXTURE(SdTiledRenderingTest, testRegenerateDiagram)
     // as the group shape is a diagram. Do the same as before done by triggering UI
     // events directly in the model
     // Remove and free top-left entry (Box showing "A")
+    // NOTE: DiagramSubObjects are now DeleteProtected and
+    // inside RemoveObject IsDeleteProtect is checked, so
+    // this intentionally no longer removes that object.
+    // To remove it the diagram command to remove it including
+    // the correct DiagramModelID of that object is needed, as
+    // is done from the DiagramDialog
     pActualPage->GetObj(0)->GetSubList()->RemoveObject(1);
 
     // select diagram
@@ -2280,12 +2286,15 @@ CPPUNIT_TEST_FIXTURE(SdTiledRenderingTest, testRegenerateDiagram)
     pXImpressDocument->postKeyEvent(LOK_KEYEVENT_KEYUP, 0, awt::Key::TAB);
     Scheduler::ProcessEventsToIdle();
 
-    CPPUNIT_ASSERT_EQUAL(static_cast<size_t>(3), pActualPage->GetObj(0)->GetSubList()->GetObjCount());
+    // see note above: four is correct for now
+    CPPUNIT_ASSERT_EQUAL(static_cast<size_t>(4), pActualPage->GetObj(0)->GetSubList()->GetObjCount());
 
     // regenerate diagram
     dispatchCommand(mxComponent, u".uno:RegenerateDiagram"_ustr, uno::Sequence<beans::PropertyValue>());
 
     // diagram content (child shape count) should be the same as in the beginning
+    // NOTE: This is due to regenerate-diagram.pptx *not* having a drawing.xml
+    // and regenerate had to be done already at load time
     CPPUNIT_ASSERT_EQUAL(static_cast<size_t>(4), pActualPage->GetObj(0)->GetSubList()->GetObjCount());
 }
 
diff --git a/sd/source/ui/docshell/docshel4.cxx b/sd/source/ui/docshell/docshel4.cxx
index ae00224932e8..1e070280503a 100644
--- a/sd/source/ui/docshell/docshel4.cxx
+++ b/sd/source/ui/docshell/docshel4.cxx
@@ -455,7 +455,9 @@ bool DrawDocShell::ImportFrom(SfxMedium &rMedium,
         mpDoc->EnableUndo(false);
     }
 
+    mpDoc->incImportExport();
     const bool bRet = SfxObjectShell::ImportFrom(rMedium, xInsertPosition);
+    mpDoc->decImportExport();
 
     SfxItemSet& rSet = rMedium.GetItemSet();
     if (SfxItemState::SET == rSet.GetItemState(SID_DOC_STARTPRESENTATION))
diff --git a/sd/source/ui/func/fusel.cxx b/sd/source/ui/func/fusel.cxx
index ccde638f8f34..9b7c244d0200 100644
--- a/sd/source/ui/func/fusel.cxx
+++ b/sd/source/ui/func/fusel.cxx
@@ -734,6 +734,7 @@ bool FuSelection::MouseButtonUp(const MouseEvent& rMEvt)
                 **************************************************************/
                 SdrPageView* pPV;
                 SdrObject* pObj = mpView->PickObj(aMDPos, mpView->getHitTolLog(), pPV, SdrSearchOptions::ALSOONMASTER | SdrSearchOptions::BEFOREMARK);
+
                 if (pObj && pPV->IsObjMarkable(pObj))
                 {
                     mpView->UnmarkAllObj();
@@ -750,13 +751,12 @@ bool FuSelection::MouseButtonUp(const MouseEvent& rMEvt)
                     pSingleObj = rMarkList.GetMark(0)->GetMarkedSdrObj();
                 }
 
-                // Check for click on svx::diagram::DiagramFrameHdl
-                // - if we hit a SdrHdl
-                // - if it was not moved
-                // - if single object is selected
-                //   - and it is a Diagram
-                if(pHdl && !bWasDragged && nullptr != pSingleObj && pSingleObj->isDiagram())
+                if(!bWasDragged && nullptr != pSingleObj && pSingleObj->isDiagram() && pHdl)
                 {
+                    // Check for click on svx::diagram::DiagramFrameHdl
+                    // - if we hit a SdrHdl
+                    // - if it was not moved
+                    // - if single object is selected and it is a Diagram
                     svx::diagram::DiagramFrameHdl* pDiagramFrameHdl(dynamic_cast<svx::diagram::DiagramFrameHdl*>(pHdl));
                     if(nullptr != pDiagramFrameHdl)
                     {
@@ -910,6 +910,23 @@ bool FuSelection::MouseButtonUp(const MouseEvent& rMEvt)
             return true;
         }
 
+        if(!bWasDragged && nullptr != pSingleObj && pSingleObj->isDiagram())
+        {
+            const std::shared_ptr< svx::diagram::DiagramHelper_svx >& rDiagramHelper(pSingleObj->getDiagramHelper());
+            if (rDiagramHelper)
+            {
+                SdrPageView* pPV;
+                SdrObject* pCandidate = mpView->PickObj(aMDPos, mpView->getHitTolLog(), pPV, SdrSearchOptions::DEEP);
+                if (pCandidate && !pCandidate->isDiagram())
+                {
+                    rDiagramHelper->markDirectDiagramSubSelection(*pCandidate);
+                    mpView->UnmarkAllObj();
+                    mpView->MarkObj(pSingleObj,pPV);
+                    return true;
+                }
+            }
+        }
+
         if ( (nSlotId != SID_OBJECT_SELECT && nMarkCount==0)                    ||
              ( mpView->GetDragMode() == SdrDragMode::Crook &&
               !mpView->IsCrookAllowed( mpView->IsCrookNoContortion() ) ) ||
diff --git a/svx/source/diagram/DiagramHelper_svx.cxx b/svx/source/diagram/DiagramHelper_svx.cxx
index 016a1722807c..2d88e9f5768b 100644
--- a/svx/source/diagram/DiagramHelper_svx.cxx
+++ b/svx/source/diagram/DiagramHelper_svx.cxx
@@ -38,6 +38,8 @@
 #include <officecfg/Office/Common.hxx>
 #include <svx/strings.hrc>
 #include <svx/dialmgr.hxx>
+#include <svx/svditer.hxx>
+#include <osl/diagnose.h>
 
 using namespace ::com::sun::star;
 
@@ -406,40 +408,52 @@ DiagramFrameHdl::DiagramFrameHdl(const basegfx::B2DHomMatrix& rTransformation)
 }
 
 DiagramHelper_svx::DiagramHelper_svx()
-: mbUseDiagramThemeData(false)
+: msSelectedModelID()
+, mbUseDiagramThemeData(false)
 , mbUseDiagramModelData(true)
 , mbForceThemePtrRecreation(false)
+, mbDiagramObjectsLocked(false)
 {
 }
 
 DiagramHelper_svx::DiagramHelper_svx(DiagramHelper_svx const& rSource)
-: mbUseDiagramThemeData(rSource.mbUseDiagramThemeData)
+: msSelectedModelID()
+, mbUseDiagramThemeData(rSource.mbUseDiagramThemeData)
 , mbUseDiagramModelData(rSource.mbUseDiagramModelData)
 , mbForceThemePtrRecreation(rSource.mbForceThemePtrRecreation)
+, mbDiagramObjectsLocked(false)
 {
 }
 
 DiagramHelper_svx::~DiagramHelper_svx() {}
 
-void DiagramHelper_svx::disconnectFromSdrObjGroup()
+SdrObjGroup* DiagramHelper_svx::getAssociatedRootShape()
 {
     uno::Reference< drawing::XShape >& rxRootShape(accessRootShape());
-    SdrObjGroup* pGroupObject(dynamic_cast<SdrObjGroup*>(SdrObject::getSdrObjectFromXShape(rxRootShape)));
-    if (nullptr != pGroupObject)
+    return dynamic_cast<SdrObjGroup*>(SdrObject::getSdrObjectFromXShape(rxRootShape));
+}
+
+void DiagramHelper_svx::disconnectFromSdrObjGroup()
+{
+    SdrObjGroup* pRootObject(getAssociatedRootShape());
+
+    if (nullptr != pRootObject)
     {
-        rxRootShape.clear();
-        pGroupObject->mp_DiagramHelper.reset();
+        // remove locks. Do this before resetting RootShape below, it uses that
+        applyLocksToDiagramObjects(false);
+        accessRootShape().clear();
+        pRootObject->mp_DiagramHelper.reset();
     }
 }
 
 void DiagramHelper_svx::connectToSdrObjGroup(const css::uno::Reference< css::drawing::XShape >& rTarget)
 {
-    SdrObjGroup* pGroupObject(nullptr);
+    SdrObjGroup* pRootObject(nullptr);
     uno::Reference< drawing::XShape >& rxRootShape(accessRootShape());
     if (rxRootShape && rTarget == rxRootShape)
     {
-        pGroupObject = dynamic_cast<SdrObjGroup*>(SdrObject::getSdrObjectFromXShape(rxRootShape));
-        if (pGroupObject != nullptr &&  pGroupObject->mp_DiagramHelper.get() == this)
+        pRootObject = dynamic_cast<SdrObjGroup*>(SdrObject::getSdrObjectFromXShape(rxRootShape));
+        if (pRootObject != nullptr &&  pRootObject->mp_DiagramHelper.get() == this)
         {
             // connection already established
             return;
@@ -451,20 +465,169 @@ void DiagramHelper_svx::connectToSdrObjGroup(const css::uno::Reference< css::dra
 
     // connect to target
     rxRootShape = rTarget;
-    pGroupObject = dynamic_cast<SdrObjGroup*>(SdrObject::getSdrObjectFromXShape(rxRootShape));
-    if (nullptr != pGroupObject)
-        pGroupObject->mp_DiagramHelper.reset(this);
+    pRootObject = dynamic_cast<SdrObjGroup*>(SdrObject::getSdrObjectFromXShape(rxRootShape));
+    if (nullptr != pRootObject)
+        pRootObject->mp_DiagramHelper.reset(this);
+
+    applyLocksToDiagramObjects(true);
 }
 
-void DiagramHelper_svx::AddAdditionalVisualization(const SdrObjGroup& rTarget, SdrHdlList& rHdlList)
+void DiagramHelper_svx::AddAdditionalVisualization(SdrHdlList& rHdlList)
 {
+    SdrObjGroup* pRootObject(getAssociatedRootShape());
+    if (nullptr == pRootObject)
+        return;
+
     // create an extra frame visualization here
     basegfx::B2DHomMatrix aTransformation;
     basegfx::B2DPolyPolygon aPolyPolygon;
-    rTarget.TRGetBaseGeometry(aTransformation, aPolyPolygon);
+    pRootObject->TRGetBaseGeometry(aTransformation, aPolyPolygon);
 
     std::unique_ptr<SdrHdl> pHdl(new DiagramFrameHdl(aTransformation));
     rHdlList.AddHdl(std::move(pHdl));
+
+    applyLocksToDiagramObjects(true);
+}
+
+void DiagramHelper_svx::applyLocksToDiagramObjects(bool bActivate)
+{
+    if (mbDiagramObjectsLocked == bActivate)
+        return;
+
+    SdrObjGroup* pRootObject(getAssociatedRootShape());
+    if (nullptr == pRootObject)
+        return;
+
+    mbDiagramObjectsLocked = bActivate;
+    SdrObjListIter aIterator(*pRootObject, SdrIterMode::DeepNoGroups);
+    while (aIterator.IsMore())
+    {
+        SdrObject* pCandidate(aIterator.Next());
+
+        if (nullptr != pCandidate)
+        {
+            if (pRootObject != pCandidate)
+            {
+                pCandidate->SetMoveProtect(bActivate);
+                pCandidate->SetResizeProtect(bActivate);
+                pCandidate->SetDeleteProtect(bActivate);
+            }
+
+            // reset name/DiagramDataModelID when deactivating which
+            // means that gets a regular SdrObjGroup
+            if (!bActivate)
+                pCandidate->setDiagramDataModelID(EMPTY_OUSTRING);
+        }
+    }
+}
+
+const OUString& DiagramHelper_svx::getSelectedModelID() const
+{
+    if (msSelectedModelID.isEmpty())
+        return getBackgroundShapeModelID();
+    return msSelectedModelID;
+}
+
+SdrObject* DiagramHelper_svx::getDiagramSubSelection()
+{
+    SdrObjGroup* pRootObject(getAssociatedRootShape());
+    if (nullptr == pRootObject || 0 == pRootObject->GetObjCount())
+        return nullptr;
+
+    // look for shape with that ID
+    const OUString& rID(getSelectedModelID());
+    SdrObjListIter aIter(pRootObject);
+
+    while(aIter.IsMore())
+    {
+        SdrObject* pObj(aIter.Next());
+        if (nullptr != pObj && pObj->getDiagramDataModelID() == rID)
+            return pObj;
+    }
+
+    OSL_FAIL("Diagram Sub-Shape with SelectedModelID not found (!)");
+    aIter.Reset();
+    return aIter.Next();
+}
+
+bool DiagramHelper_svx::markNextDiagramSubSelection(bool bPrev)
+{
+    SdrObjGroup* pRootObject(getAssociatedRootShape());
+    if (nullptr == pRootObject || 0 == pRootObject->GetObjCount())
+        return false;
+
+    SdrObject* pObj(nullptr);
+    const OUString& rID(getSelectedModelID());
+
+    // find selected shape
+    SdrObjListIter aIter(pRootObject, SdrIterMode::DeepNoGroups, !bPrev);
+
+    while(aIter.IsMore())
+    {
+        pObj = aIter.Next();
+
+        if (nullptr != pObj && pObj->getDiagramDataModelID() == rID)
+        {
+            // a is currently selected shape
+            if (!aIter.IsMore())
+                // last shape reached, return without usage
+                return false;
+
+            pObj = aIter.Next();
+            break;
+        }
+    }
+
+    if (nullptr == pObj)
+        return false;
+
+    setSelectedModelID(pObj->getDiagramDataModelID());
+    return true;
+}
+
+void DiagramHelper_svx::initSelectionByKeyboard(bool bPrev)
+{
+    SdrObjGroup* pRootObject(getAssociatedRootShape());
+    if (nullptr == pRootObject || 0 == pRootObject->GetObjCount())
+        return;
+
+    SdrObjListIter aIter(pRootObject, SdrIterMode::DeepNoGroups, !bPrev);
+    SdrObject* pObj(aIter.Next());
+
+    if (nullptr == pObj)
+        return;
+
+    setSelectedModelID(pObj->getDiagramDataModelID());
+}
+
+void DiagramHelper_svx::markDirectDiagramSubSelection(SdrObject& rCandidate)
+{
+    if (rCandidate.isDiagram() || rCandidate.getDiagramDataModelID().isEmpty())
+        // it's directly the root of a Diagram or not a SdrObject associated
+        // with Diagrams at all
+        return;
+
+    SdrObjGroup* pRootObject(getAssociatedRootShape());
+    if (nullptr == pRootObject || 0 == pRootObject->GetObjCount())
+        return;
+
+    // find selected shape
+    SdrObjListIter aIter(pRootObject);
+
+    while(aIter.IsMore())
+    {
+        SdrObject* pObj(aIter.Next());
+
+        if (pObj == &rCandidate)
+        {
+            // found object in Diagram based on pRootObject. Set
+            // selected object
+            setSelectedModelID(rCandidate.getDiagramDataModelID());
+            return;
+        }
+    }
+
+    setSelectedModelID(getBackgroundShapeModelID());
 }
 
 DiagramHelperFactory_svx::DiagramHelperFactory_svx()
diff --git a/svx/source/diagram/datamodel_svx.cxx b/svx/source/diagram/datamodel_svx.cxx
index 738403b3f5f0..d7daa2a235a8 100644
--- a/svx/source/diagram/datamodel_svx.cxx
+++ b/svx/source/diagram/datamodel_svx.cxx
@@ -24,11 +24,13 @@
 #include <svx/diagram/datamodel_svx.hxx>
 #include <svx/svdobj.hxx>
 #include <svx/svditer.hxx>
+#include <svx/svdogrp.hxx>
 #include <comphelper/xmltools.hxx>
 #include <sal/log.hxx>
 #include <utility>
 #include <sax/fastattribs.hxx>
 #include <com/sun/star/text/XText.hpp>
+#include <com/sun/star/drawing/XShapes.hpp>
 #include <xmloff/xmltoken.hxx>
 
 using namespace ::oox;
@@ -510,17 +512,36 @@ DomMapFlags DiagramData_svx::removeDiagramNode(const OUString& rNodeId)
     return aRetval;
 }
 
-DiagramDataState::DiagramDataState(Connections aConnections, Points aPoints)
-: maConnections(std::move(aConnections))
-, maPoints(std::move(aPoints))
+DiagramDataState::DiagramDataState(const Connections& aConnections, const Points& aPoints, const uno::Reference< drawing::XShape >& rRootShape)
+: maConnections(aConnections)
+, maPoints(aPoints)
+, mxShapes()
+, maTransformation()
 {
+    SdrObjGroup* pSource(dynamic_cast<SdrObjGroup*>(SdrObject::getSdrObjectFromXShape(rRootShape)));
+    if (nullptr != pSource)
+    {
+        basegfx::B2DPolyPolygon aPolyPolygon;
+        pSource->TRGetBaseGeometry(maTransformation, aPolyPolygon);
+
+        for(size_t a(0); a < pSource->GetObjCount(); a++)
+        {
+            SdrObject* pCandidate(pSource->GetObj(a));
+
+            if (nullptr != pCandidate)
+            {
+                uno::Reference<drawing::XShape> xCandidate(pCandidate->getUnoShape());
+                mxShapes.push_back(xCandidate);
+            }
+        }
+    }
 }
 
 DiagramDataStatePtr DiagramData_svx::extractDiagramDataState() const
 {
     // Just copy all Connections && Points. The shared_ptr data in
     // Point-entries is no problem, it just continues exiting shared
-    return std::make_shared< DiagramDataState >(maConnections, maPoints);
+    return std::make_shared< DiagramDataState >(maConnections, maPoints, accessRootShape());
 }
 
 void DiagramData_svx::applyDiagramDataState(const DiagramDataStatePtr& rState)
@@ -530,6 +551,25 @@ void DiagramData_svx::applyDiagramDataState(const DiagramDataStatePtr& rState)
         maConnections = rState->getConnections();
         maPoints = rState->getPoints();
 
+        uno::Reference<drawing::XShapes> xRootShape(accessRootShape(), uno::UNO_QUERY);
+        if (xRootShape.is())
+        {
+            SdrObjGroup* pTarget(dynamic_cast<SdrObjGroup*>(SdrObject::getSdrObjectFromXShape(xRootShape)));
+
+            if (nullptr != pTarget)
+            {
+                // Delete all existing shapes in that group
+                pTarget->getChildrenOfSdrObject()->ClearSdrObjList();
+            }
+
+            const std::vector<uno::Reference<drawing::XShape>>& rXShapes(rState->getXShapes());
+            for (auto& rShape : rXShapes)
+                xRootShape->add(rShape);
+
+            basegfx::B2DPolyPolygon aPolyPolygon;
+            pTarget->TRSetBaseGeometry(rState->getTransformation(), aPolyPolygon);
+        }
+
         // Reset temporary buffered ModelData association lists & rebuild them
         // and the Diagram DataModel. Do that here *immediately* to prevent
         // re-usage of potentially invalid Connection/Point objects
diff --git a/svx/source/sdr/properties/attributeproperties.cxx b/svx/source/sdr/properties/attributeproperties.cxx
index 697fdb88620d..8482d8f950c1 100644
--- a/svx/source/sdr/properties/attributeproperties.cxx
+++ b/svx/source/sdr/properties/attributeproperties.cxx
@@ -35,6 +35,7 @@
 #include <svx/xflhtit.hxx>
 #include <svx/svdmodel.hxx>
 #include <svx/svdpage.hxx>
+#include <svx/diagram/DiagramHelper_svx.hxx>
 #include <osl/diagnose.h>
 
 namespace sdr::properties
@@ -270,7 +271,7 @@ namespace sdr::properties
             return *moItemSet;
         }
 
-        void AttributeProperties::ItemSetChanged(std::span< const SfxPoolItem* const > /*aChangedItems*/, sal_uInt16 /*nDeletedWhich*/, bool /*bAdjustTextFrameWidthAndHeight*/)
+        void AttributeProperties::ItemSetChanged(std::span< const SfxPoolItem* const > aChangedItems, sal_uInt16 /*nDeletedWhich*/, bool /*bAdjustTextFrameWidthAndHeight*/)
         {
             // own modifications
             SdrObject& rObj = GetSdrObject();
@@ -278,6 +279,13 @@ namespace sdr::properties
             rObj.SetBoundRectDirty();
             rObj.SetBoundAndSnapRectsDirty(/*bNotMyself*/true);
             rObj.SetChanged();
+
+            if (!rObj.getDiagramDataModelID().isEmpty() && !rObj.getSdrModelFromSdrObject().isInImportExport())
+            {
+                const std::shared_ptr< svx::diagram::DiagramHelper_svx >& pDiagramHelper(rObj.getDiagramHelper());
+                if (pDiagramHelper)
+                    pDiagramHelper->ItemSetInformationChange(aChangedItems);
+            }
         }
 
         void AttributeProperties::ItemChange(const sal_uInt16 nWhich, const SfxPoolItem* pNewItem)
diff --git a/svx/source/svdraw/svdedtv.cxx b/svx/source/svdraw/svdedtv.cxx
index 15fff60a8490..1eb49733fd0b 100644
--- a/svx/source/svdraw/svdedtv.cxx
+++ b/svx/source/svdraw/svdedtv.cxx
@@ -36,6 +36,7 @@
 #include <svx/xfillit0.hxx>
 #include <osl/diagnose.h>
 #include <sfx2/viewsh.hxx>
+#include <comphelper/dispatchcommand.hxx>
 
 #include <com/sun/star/lang/XServiceInfo.hpp>
 
@@ -559,7 +560,16 @@ void SdrEditView::CheckPossibilities()
 
         for (size_t nm=0; nm<nMarkCount; ++nm) {
             const SdrMark* pM=rMarkList.GetMark(nm);
-            const SdrObject* pObj=pM->GetMarkedSdrObj();
+            SdrObject* pObj=pM->GetMarkedSdrObj();
+
+            // try to get DiagramSubSelection
+            if(nullptr != pObj)
+            {
+                SdrObject* pSubSelection(pObj->getDiagramSubSelection());
+                if(nullptr != pSubSelection && !pSubSelection->isDiagramBackgroundShape())
+                    pObj = pSubSelection;
+            }
+
             const SdrPageView* pPV=pM->GetPageView();
             if (pPV!=pPV0) {
                 if (pPV->IsReadOnly()) m_bReadOnly=true;
@@ -799,10 +809,29 @@ static void lcl_LazyDelete(std::vector<rtl::Reference<SdrObject>> & rLazyDelete)
 void SdrEditView::DeleteMarkedObj()
 {
     const SdrMarkList& rMarkList = GetMarkedObjectList();
+    const size_t nMarkCount(rMarkList.GetMarkCount());
+
     // #i110981# return when nothing is to be done at all
-    if(!rMarkList.GetMarkCount())
-    {
+    if(0 == nMarkCount)
         return;
+
+    if (1 == nMarkCount)
+    {
+        SdrObject* pObj(rMarkList.GetMark(0)->GetMarkedSdrObj());
+
+        if (nullptr != pObj)
+        {
+            SdrObject* pSubSelection(pObj->getDiagramSubSelection());
+
+            if (nullptr != pSubSelection && pSubSelection->isDiagramTextNode())
+            {
+                if (pSubSelection->removeDiagramNode())
+                {
+                    comphelper::dispatchCommand(u".uno:RegenerateDiagram"_ustr, {});
+                    return;
+                }
+            }
+        }
     }
 
     // moved breaking action and undo start outside loop
diff --git a/svx/source/svdraw/svdedtv1.cxx b/svx/source/svdraw/svdedtv1.cxx
index 77c0585d63dc..2ccc9778464a 100644
--- a/svx/source/svdraw/svdedtv1.cxx
+++ b/svx/source/svdraw/svdedtv1.cxx
@@ -954,6 +954,8 @@ void SdrEditView::MergeAttrFromMarked(SfxItemSet& rAttr, bool bOnlyHardAttr) con
             continue;
         }
 
+        pObj = pObj->getDiagramSubSelection();
+
         const SfxItemSet& rSet = pObj->GetMergedItemSet();
         SfxWhichIter aIter(rSet);
         sal_uInt16 nWhich(aIter.FirstWhich());
@@ -1199,6 +1201,8 @@ void SdrEditView::SetAttrToMarked(const SfxItemSet& rAttr, bool bReplaceAll)
         SdrMark* pM=rMarkList.GetMark(nm);
         SdrObject* pObj = pM->GetMarkedSdrObj();
 
+        pObj = pObj->getDiagramSubSelection();
+
         if( bUndo )
         {
             SdrEdgeObj* pEdgeObj = dynamic_cast< SdrEdgeObj* >( pObj );
diff --git a/svx/source/svdraw/svdmark.cxx b/svx/source/svdraw/svdmark.cxx
index fc5d815ab9a2..8c965cbd34b7 100644
--- a/svx/source/svdraw/svdmark.cxx
+++ b/svx/source/svdraw/svdmark.cxx
@@ -26,6 +26,7 @@
 #include <svx/svdpagv.hxx>
 #include <svx/strings.hrc>
 #include <svx/dialmgr.hxx>
+#include <svx/diagram/DiagramHelper_svx.hxx>
 
 
 #include <svl/SfxBroadcaster.hxx>
@@ -591,9 +592,11 @@ bool SdrMarkList::TakeBoundRect(SdrPageView const * pPV, tools::Rectangle& rRect
 
         if(!pPV || pMark->GetPageView() == pPV)
         {
-            if(pMark->GetMarkedSdrObj())
+            SdrObject* pCandidate(pMark->GetMarkedSdrObj());
+
+            if(pCandidate)
             {
-                aR = pMark->GetMarkedSdrObj()->GetCurrentBoundRect();
+                aR = pCandidate->GetCurrentBoundRect();
 
                 if(bFnd)
                 {
@@ -621,9 +624,11 @@ bool SdrMarkList::TakeSnapRect(SdrPageView const * pPV, tools::Rectangle& rRect)
 
         if(!pPV || pMark->GetPageView() == pPV)
         {
-            if(pMark->GetMarkedSdrObj())
+            SdrObject* pCandidate(pMark->GetMarkedSdrObj());
+
+            if(pCandidate)
             {
-                tools::Rectangle aR(pMark->GetMarkedSdrObj()->GetSnapRect());
+                tools::Rectangle aR(pCandidate->GetSnapRect());
 
                 if(bFnd)
                 {
diff --git a/svx/source/svdraw/svdmrkv.cxx b/svx/source/svdraw/svdmrkv.cxx
index 71ca451f6d64..d98cdfb40b27 100644
--- a/svx/source/svdraw/svdmrkv.cxx
+++ b/svx/source/svdraw/svdmrkv.cxx
@@ -24,6 +24,8 @@
 #include <svx/svdpage.hxx>
 #include <svx/svdotable.hxx>
 #include <svx/svdomedia.hxx>
+#include <svx/svdogrp.hxx>
+#include <svx/diagram/DiagramHelper_svx.hxx>
 
 #include <osl/diagnose.h>
 #include <osl/thread.h>
@@ -1457,6 +1459,7 @@ void SdrMarkView::SetMarkHandles(SfxViewShell* pOtherShell)
         {
             // otherwise nothing is found
             const size_t nSiz0(maHdlList.GetHdlCount());
+            SdrObject* pSubSelection(nullptr);
 
             if( bSingleTextObjMark )
             {
@@ -1464,6 +1467,21 @@ void SdrMarkView::SetMarkHandles(SfxViewShell* pOtherShell)
             }
             else
             {
+                // caution! mpMarkedObj and pSubSelection are and may only be set for
+                // single object selection
+                if (nullptr != mpMarkedObj)
+                    pSubSelection = mpMarkedObj->getDiagramSubSelection();
+
+                // use SubSelection not for BGShape, in that case use SdrObjGroup to
+                // allow group actions on it
+                if(nullptr != pSubSelection)
+                {
+                    if (pSubSelection->isDiagramBackgroundShape())
+                        pSubSelection = nullptr;
+                    else
+                        aRect = pSubSelection->GetSnapRect();
+                }
+
                 const bool bWdt0(aRect.Left() == aRect.Right());
                 const bool bHgt0(aRect.Top() == aRect.Bottom());
 
@@ -1532,7 +1550,7 @@ void SdrMarkView::SetMarkHandles(SfxViewShell* pOtherShell)
             for (size_t i=nSiz0; i<nSiz1; ++i)
             {
                 SdrHdl* pHdl=maHdlList.GetHdl(i);
-                pHdl->SetObj(mpMarkedObj);
+                pHdl->SetObj(nullptr != pSubSelection ? pSubSelection : mpMarkedObj);
                 pHdl->SetPageView(mpMarkedPV);
                 pHdl->SetObjHdlNum(sal_uInt16(i-nSiz0));
             }
@@ -2101,7 +2119,13 @@ bool SdrMarkView::IsMarkedObjHit(const Point& rPnt, short nTol) const
     const SdrMarkList& rMarkList = GetMarkedObjectList();
     for (size_t nm=0; nm<rMarkList.GetMarkCount() && !bRet; ++nm) {
         SdrMark* pM=rMarkList.GetMark(nm);
-        bRet = nullptr != CheckSingleSdrObjectHit(rPnt,sal_uInt16(nTol),pM->GetMarkedSdrObj(),pM->GetPageView(),SdrSearchOptions::NONE,nullptr);
+        SdrObject* pObj(pM->GetMarkedSdrObj());
+
+        // access possible SubSelectio
+        if (nullptr != pObj)
+            pObj = pObj->getDiagramSubSelection();
+
+        bRet = nullptr != CheckSingleSdrObjectHit(rPnt,sal_uInt16(nTol),pObj,pM->GetPageView(),SdrSearchOptions::NONE,nullptr);
     }
     return bRet;
 }
@@ -2121,7 +2145,31 @@ bool SdrMarkView::MarkObj(const Point& rPnt, short nTol, bool bToggle, bool bDee
     SdrSearchOptions nOptions=SdrSearchOptions::PICKMARKABLE;
     if (bDeep) nOptions=nOptions|SdrSearchOptions::DEEP;
     SdrObject* pObj = PickObj(rPnt, static_cast<sal_uInt16>(nTol), pPV, nOptions);
-    if (pObj) {
+
+    if (pObj)
+    {
+        const std::shared_ptr< svx::diagram::DiagramHelper_svx >& rDiagramHelper(pObj->getDiagramHelper());
+        if (rDiagramHelper)
+        {
+            if (pObj->isDiagram() && !bDeep)
+            {
+                // Klick on Diagram, look again but deep to get possibly an object
+                // inside the SdrObjGroup associated with it
+                SdrObject* pCandidate = PickObj(rPnt, static_cast<sal_uInt16>(nTol), pPV, nOptions|SdrSearchOptions::DEEP);
+
+                if (pCandidate && !pCandidate->isDiagram())
+                    rDiagramHelper->markDirectDiagramSubSelection(*pCandidate);
+            }
+            else
+            {
+                rDiagramHelper->markDirectDiagramSubSelection(*pObj);
+                pObj = rDiagramHelper->getAssociatedRootShape();
+            }
+        }
+    }
+
+    if (pObj)
+    {
         bool bUnmark=bToggle && IsObjMarked(pObj);
         MarkObj(pObj,pPV,bUnmark);
     }
@@ -2139,35 +2187,67 @@ bool SdrMarkView::MarkNextObj(bool bPrev)
 
     const SdrMarkList& rMarkList = GetMarkedObjectList();
     rMarkList.ForceSort();
-    const size_t nMarkCount=rMarkList.GetMarkCount();
-    size_t nChgMarkNum = SAL_MAX_SIZE; // number of the MarkEntry we want to replace
-    size_t nSearchObjNum = bPrev ? 0 : SAL_MAX_SIZE;
-    if (nMarkCount!=0) {
-        nChgMarkNum=bPrev ? 0 : nMarkCount-1;
-        SdrMark* pM=rMarkList.GetMark(nChgMarkNum);
-        assert(pM != nullptr);
-        if (pM->GetMarkedSdrObj() != nullptr)
-            nSearchObjNum = pM->GetMarkedSdrObj()->GetNavigationPosition();
-    }
+    const size_t nMarkCount(rMarkList.GetMarkCount());
+    size_t nChgMarkNum(SAL_MAX_SIZE); // number of the MarkEntry we want to replace
+    SdrObject* pMarkObj(nullptr);
 
-    SdrObject* pMarkObj=nullptr;
-    SdrObjList* pSearchObjList=pPageView->GetObjList();
-    const size_t nObjCount = pSearchObjList->GetObjCount();
-    if (nObjCount!=0) {
-        if (nSearchObjNum>nObjCount) nSearchObjNum=nObjCount;
-        while (pMarkObj==nullptr && ((!bPrev && nSearchObjNum>0) || (bPrev && nSearchObjNum<nObjCount)))
+    if (1 == nMarkCount)
+    {
+        SdrMark* pM(rMarkList.GetMark(0));
+        if (nullptr != pM)
         {
-            if (!bPrev)
-                nSearchObjNum--;
-            SdrObject* pSearchObj = pSearchObjList->GetObjectForNavigationPosition(nSearchObjNum);
-            if (IsObjMarkable(pSearchObj,pPageView))
+            SdrObject* pCandidate(pM->GetMarkedSdrObj());
+
+            if (nullptr != pCandidate)
             {
-                if (rMarkList.FindObject(pSearchObj)==SAL_MAX_SIZE)
+                const std::shared_ptr< svx::diagram::DiagramHelper_svx >& rDiagramHelper(pCandidate->getDiagramHelper());
+
+                if (rDiagramHelper)
                 {
-                    pMarkObj=pSearchObj;
+                    if (rDiagramHelper->markNextDiagramSubSelection(bPrev))
+                        pMarkObj=pCandidate;
                 }
             }
-            if (bPrev) nSearchObjNum++;
+        }
+    }
+
+    if (nullptr == pMarkObj)
+    {
+        size_t nSearchObjNum = bPrev ? 0 : SAL_MAX_SIZE;
+        if (nMarkCount!=0) {
+            nChgMarkNum=bPrev ? 0 : nMarkCount-1;
+            SdrMark* pM=rMarkList.GetMark(nChgMarkNum);
+            assert(pM != nullptr);
+            if (pM->GetMarkedSdrObj() != nullptr)
+                nSearchObjNum = pM->GetMarkedSdrObj()->GetNavigationPosition();
+        }
+
+        SdrObjList* pSearchObjList=pPageView->GetObjList();
+        const size_t nObjCount = pSearchObjList->GetObjCount();
+        if (nObjCount!=0) {
+            if (nSearchObjNum>nObjCount) nSearchObjNum=nObjCount;
+            while (pMarkObj==nullptr && ((!bPrev && nSearchObjNum>0) || (bPrev && nSearchObjNum<nObjCount)))
+            {
+                if (!bPrev)
+                    nSearchObjNum--;
+                SdrObject* pSearchObj = pSearchObjList->GetObjectForNavigationPosition(nSearchObjNum);
+                if (IsObjMarkable(pSearchObj,pPageView))
+                {
+                    if (rMarkList.FindObject(pSearchObj)==SAL_MAX_SIZE)
+                    {
+                        pMarkObj=pSearchObj;
+                    }
+                }
+                if (bPrev) nSearchObjNum++;
+            }
+
+            if (nullptr != pMarkObj && pMarkObj->IsGroupObject() && pMarkObj->isDiagram())
+            {
+                // newly selected by keyboard, reset old sub selection
+                const std::shared_ptr< svx::diagram::DiagramHelper_svx >& rDiagramHelper(pMarkObj->getDiagramHelper());
+                if (rDiagramHelper)
+                    rDiagramHelper->initSelectionByKeyboard(bPrev);
+            }
         }
     }
 
@@ -2809,6 +2889,9 @@ tools::Rectangle SdrMarkView::GetMarkedObjBoundRect() const
     for (size_t nm=0; nm<rMarkList.GetMarkCount(); ++nm) {
         SdrMark* pM=rMarkList.GetMark(nm);
         SdrObject* pO=pM->GetMarkedSdrObj();
+        if (!pO)
+            continue;
+
         tools::Rectangle aR1(pO->GetCurrentBoundRect());
         if (aRect.IsEmpty()) aRect=aR1;
         else aRect.Union(aR1);
@@ -2828,6 +2911,7 @@ const tools::Rectangle& SdrMarkView::GetMarkedObjRect() const
             SdrObject* pO = pM->GetMarkedSdrObj();
             if (!pO)
                 continue;
+
             tools::Rectangle aR1(pO->GetSnapRect());
             if (aRect.IsEmpty()) aRect=aR1;
             else aRect.Union(aR1);
diff --git a/svx/source/svdraw/svdoashp.cxx b/svx/source/svdraw/svdoashp.cxx
index 27d585532ff8..91cafc08df19 100644
--- a/svx/source/svdraw/svdoashp.cxx
+++ b/svx/source/svdraw/svdoashp.cxx
@@ -2611,7 +2611,7 @@ void SdrObjCustomShape::EndTextEdit( SdrOutliner& rOutl )
 {
     if (!getDiagramDataModelID().isEmpty())
     {
-        std::shared_ptr< svx::diagram::DiagramHelper_svx > pIDiagramHelper(getDiagramHelperFromDiagramOrMember());
+        std::shared_ptr< svx::diagram::DiagramHelper_svx > pIDiagramHelper(getDiagramHelper());
 
         if (pIDiagramHelper)
         {
diff --git a/svx/source/svdraw/svdobj.cxx b/svx/source/svdraw/svdobj.cxx
index 842f16438787..c3a940c48467 100644
--- a/svx/source/svdraw/svdobj.cxx
+++ b/svx/source/svdraw/svdobj.cxx
@@ -50,6 +50,7 @@
 #include <vector>
 
 #include <svx/svdotable.hxx>
+#include <svx/diagram/DiagramHelper_svx.hxx>
 
 #include <svx/sdr/contact/displayinfo.hxx>
 #include <sdr/contact/objectcontactofobjlistpainter.hxx>
@@ -244,6 +245,45 @@ const OUString& SdrObject::getDiagramDataModelID() const
     return EMPTY_OUSTRING;
 }
 
+bool SdrObject::isDiagramBackgroundShape() const
+{
+    const OUString& rID(getDiagramDataModelID());
+    if (rID.isEmpty())
+        return false;
+
+    const std::shared_ptr< svx::diagram::DiagramHelper_svx >& rDiagramHelper(getDiagramHelper());
+    if (!rDiagramHelper)
+        return false;
+
+    return rID == rDiagramHelper->getBackgroundShapeModelID();
+}
+
+bool SdrObject::isDiagramTextNode() const
+{
+    const OUString& rID(getDiagramDataModelID());
+    if (rID.isEmpty())
+        return false;
+
+    const std::shared_ptr< svx::diagram::DiagramHelper_svx >& rDiagramHelper(getDiagramHelper());
+    if (!rDiagramHelper)
+        return false;
+
+    return rDiagramHelper->isTextNodeModelID(rID);
+}
+
+bool SdrObject::removeDiagramNode()
+{
+    const OUString& rID(getDiagramDataModelID());
+    if (rID.isEmpty())
+        return false;
+
+    const std::shared_ptr< svx::diagram::DiagramHelper_svx >& rDiagramHelper(getDiagramHelper());
+    if (!rDiagramHelper)
+        return false;
+
+    return rDiagramHelper->removeDiagramNode(rID, getSdrModelFromSdrObject());
+}
+
 bool SdrObject::isDiagram() const
 {
     return false;
@@ -251,22 +291,21 @@ bool SdrObject::isDiagram() const
 
 const std::shared_ptr< svx::diagram::DiagramHelper_svx >& SdrObject::getDiagramHelper() const
 {
+    if (!getDiagramDataModelID().isEmpty())
+    {
+        SdrObject* pParent(getParentSdrObjectFromSdrObject());
+
+        if (nullptr != pParent)
+            return pParent->getDiagramHelper();
+    }
+
     static std::shared_ptr< svx::diagram::DiagramHelper_svx > aEmpty;
     return aEmpty;
 }
 
-const std::shared_ptr< svx::diagram::DiagramHelper_svx >& SdrObject::getDiagramHelperFromDiagramOrMember() const
+SdrObject* SdrObject::getDiagramSubSelection()
 {
-    SdrObject* pCurrent(const_cast<SdrObject*>(this));
-
-    while (pCurrent)
-    {
-        if (pCurrent->isDiagram())
-            return pCurrent->getDiagramHelper();
-        pCurrent = pCurrent->getParentSdrObjectFromSdrObject();
-    }
-
-    return getDiagramHelper();
+    return this;
 }
 
 // BaseProperties section
diff --git a/svx/source/svdraw/svdogrp.cxx b/svx/source/svdraw/svdogrp.cxx
index 262951347e2e..800f70d18bcf 100644
--- a/svx/source/svdraw/svdogrp.cxx
+++ b/svx/source/svdraw/svdogrp.cxx
@@ -46,6 +46,16 @@ const std::shared_ptr< svx::diagram::DiagramHelper_svx >& SdrObjGroup::getDiagra
     return mp_DiagramHelper;
 }
 
+SdrObject* SdrObjGroup::getDiagramSubSelection()
+{
+    if (!mp_DiagramHelper)
+        return this;
+
+    SdrObject* pRetval(mp_DiagramHelper->getDiagramSubSelection());
+
+    return nullptr == pRetval ? this : pRetval;
+}
+
 // BaseProperties section
 std::unique_ptr<sdr::properties::BaseProperties> SdrObjGroup::CreateObjectSpecificProperties()
 {
@@ -109,7 +119,7 @@ void SdrObjGroup::AddToHdlList(SdrHdlList& rHdlList) const
     if(!isDiagram())
         return;
 
-    svx::diagram::DiagramHelper_svx::AddAdditionalVisualization(*this, rHdlList);
+    getDiagramHelper()->AddAdditionalVisualization(rHdlList);
 }
 
 SdrObjGroup::~SdrObjGroup()
diff --git a/svx/source/svdraw/svdpage.cxx b/svx/source/svdraw/svdpage.cxx
index 97cf50a4fb4a..e01ea69e527b 100644
--- a/svx/source/svdraw/svdpage.cxx
+++ b/svx/source/svdraw/svdpage.cxx
@@ -408,7 +408,7 @@ rtl::Reference<SdrObject> SdrObjList::RemoveObject(size_t nObjNum)
 
     const size_t nCount = GetObjCount();
     rtl::Reference<SdrObject> pObj=maList[nObjNum];
-    if (pObj->IsDeleteProtect())
+    if (pObj->IsDeleteProtect() && !pObj->getSdrModelFromSdrObject().isInImportExport())
         return nullptr;
     RemoveObjectFromContainer(nObjNum);
 
diff --git a/svx/source/svdraw/svdundo.cxx b/svx/source/svdraw/svdundo.cxx
index fe735d1e32b4..018168f7e68f 100644
--- a/svx/source/svdraw/svdundo.cxx
+++ b/svx/source/svdraw/svdundo.cxx
@@ -635,15 +635,13 @@ SdrUndoDiagramModelData::SdrUndoDiagramModelData(SdrObject& rNewObj, const svx::
 , m_aStartState(rStartState)
 , m_aEndState()
 {
-    if(rNewObj.isDiagram())
-        m_aEndState = rNewObj.getDiagramHelper()->extractDiagramDataState();
 }
 
 SdrUndoDiagramModelData::~SdrUndoDiagramModelData()
 {
 }
 
-void SdrUndoDiagramModelData::implUndoRedo(bool bUndo)
+void SdrUndoDiagramModelData::Undo()
 {
     if(!mxObj)
         return;
@@ -651,19 +649,26 @@ void SdrUndoDiagramModelData::implUndoRedo(bool bUndo)
     if(!mxObj->isDiagram())
         return;
 
-    mxObj->getDiagramHelper()->applyDiagramDataState(
-        bUndo ? m_aStartState : m_aEndState);
-    mxObj->getDiagramHelper()->reLayout();
-}
+    if (!m_aEndState)
+        m_aEndState = mxObj->getDiagramHelper()->extractDiagramDataState();
 
-void SdrUndoDiagramModelData::Undo()
-{
-    implUndoRedo(true);
+    mxObj->getDiagramHelper()->applyDiagramDataState(m_aStartState);
+    mxObj->getDiagramHelper()->reLayout();
 }
 
 void SdrUndoDiagramModelData::Redo()
 {
-    implUndoRedo(false);
+    if (!m_aEndState)
+        return;
+
+    if(!mxObj)
+        return;
+
+    if(!mxObj->isDiagram())
+        return;
+
+    mxObj->getDiagramHelper()->applyDiagramDataState(m_aEndState);
+    mxObj->getDiagramHelper()->reLayout();
 }
 
 OUString SdrUndoDiagramModelData::GetComment() const