123091: Request repaints of panels on every deck layouting.

sfx2/source/sidebar/DeckLayouter.cxx

@@ -262,6 +262,7 @@ sal_Int32 DeckLayouter::PlacePanels (
 
             // Place the panel.
             rPanel.SetPosSizePixel(0, nY, nWidth, nPanelHeight);
+            rPanel.Invalidate();
 
             nY += nPanelHeight;
         }