tdf#152257 popup already launched, don't relaunch

Change-Id: I2503803b756fed179f6aa62cee2c549b6bc7c3c8
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/149972
Tested-by: Jenkins
Reviewed-by: Caolán McNamara <caolanm@redhat.com>

sw/source/core/crsr/contentcontrolbutton.cxx

@@ -88,6 +88,8 @@ void SwContentControlButton::MouseButtonDown(const MouseEvent&) { StartPopup();
 
 void SwContentControlButton::StartPopup()
 {
+    if (m_xPopup) // tdf#152257 already launched, don't relaunch
+        return;
     LaunchPopup();
     Invalidate();
 }