Applied rowspan patch #15276 (dghart)


git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@74293 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
virtual method hiding in GTK, so add direct implementation

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@74294 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775