Merged revision(s) 1751-2227 from trunk/Src/UShowCaseCtrl.pas:
Changes TShowCaseCtrl not redraw itself when invalidated. This prevents it from overwriting any showcased control.
This fixes bug #3559156 (http://bit.ly/TKXYQ7): "Previews" disappearing in Preferences dialogue box" for 3.x branch.
Authored by: delphidabbler 2012-08-18
Parent: [r2227]
Child: [r2229]
