As far as I can tell .odp spec doesn't recognize 'fadeovercolor' as a subtype of 'fade' (it's an LO extension?). But it's already saved by LO if used, so save the color properly as well. Reading it already works too. Change-Id: I30e464123f17d513fd0eaa32797f06e76a91d532 Reviewed-on: https://gerrit.libreoffice.org/c/core/+/106505 Tested-by: Jenkins Reviewed-by: Luboš Luňák <l.lunak@collabora.com>