Resolves: tdf#101588, do not prevent color de-selection tdf#96382 follow-up

Comparing colors to determine whether to set one in the result item set does
not work if the color previously was set before SaveValue() was called
unconditionally even for the "undetermined" color state. Actually we want to
know whether the user selected a color instead.

Change-Id: I508f791684ebd79ba4af9cb654f9aa0bb25bff5d

cui/source/tabpages/backgrnd.cxx

@@ -684,7 +684,7 @@ bool SvxBackgroundTabPage::FillItemSet( SfxItemSet* rCoreSet )
             {
                 // Brush-treatment:
                 if ( rOldItem.GetColor() != aBgdColor ||
-                     (SfxItemState::DEFAULT >= eOldItemState && m_pBackgroundColorSet->GetSavedValue() != m_pBackgroundColorSet->GetSelectItemId()))
+                     (SfxItemState::DEFAULT >= eOldItemState && !m_pBackgroundColorSet->IsNoSelection()))
                 {
                     bModified = true;
                     rCoreSet->Put( SvxBrushItem( aBgdColor, nWhich ) );
@@ -1423,9 +1423,13 @@ void SvxBackgroundTabPage::FillControls_Impl( const SvxBrushItem& rBgdAttr,
         }
         else
         {
+            bool bNoSelection = m_pBackgroundColorSet->IsNoSelection();
             m_pBackgroundColorSet->SelectItem( nCol );
+            m_pBackgroundColorSet->SaveValue();
+            // The actual selection is user set, not what we preset.
+            if (bNoSelection)
+                m_pBackgroundColorSet->SetNoSelection();
         }
-        m_pBackgroundColorSet->SaveValue();
 
         m_pPreviewWin1->NotifyChange( aBgdColor );