Resolves: tdf#124058 factor bitmap page into size req when its toggled on

post ctor time

Change-Id: I8257c8ffdfc4dab9893ab7d2d67e218dd3f8097c
Reviewed-on: https://gerrit.libreoffice.org/69353
Tested-by: Jenkins
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>

cui/source/tabpages/backgrnd.cxx

@@ -1565,6 +1565,7 @@ void SvxBkgTabPage::PageCreated(const SfxAllItemSet& aSet)
         }
         if (nFlags & SvxBackgroundTabFlags::SHOW_SELECTOR)
             m_xBtnBitmap->show();
+        SetOptimalSize(GetDialogController());
     }
 
     if ( bCharBackColor )

cui/source/tabpages/tparea.cxx

@@ -121,6 +121,8 @@ SvxAreaTabPage::SvxAreaTabPage(TabPageParent pParent, const SfxItemSet& rInAttrs
 
 void SvxAreaTabPage::SetOptimalSize(weld::DialogController* pController)
 {
+    m_xFillTab->set_size_request(-1, -1);
+
     TabPageParent aFillTab(m_xFillTab.get(), pController);
     // TEMP
     if (!aFillTab.pController)