jvcllaz: Update TJvDialButton to recent fix in main repo.

git-svn-id: https://svn.code.sf.net/p/lazarus-ccr/svn@6853 8e941d3f-bd1b-0410-a28a-d453659cc2b4

components/jvcllaz/run/JvHMI/jvdialbutton.pas

@@ -454,6 +454,7 @@ begin
   if APosition <> FPosition then
   begin
     FPosition := APosition;
+    BitmapNeeded;
     DrawPointer;
     lChanged := True;
   end;