Fixed disabled controls fade bug in world preferences. See comment.

Author: worstje

dialogs/world_prefs/TreePropertySheet.cpp

@@ -207,7 +207,17 @@ void	 CTreePropertySheet::OnSelChanged(
 	int		dwPage=m_cTreeCtrl.GetItemData(pNotify->itemNew.hItem);
 	LockWindowUpdate();
   if (GetPageIndex(GetActivePage()) != dwPage)    // NJG
+  {
+	  /* Theming has these nice fades inbetween controls being disabled and enabled.
+	   * That is all nice and well, but switching a page for the _first_ time since
+	   * the dialog had been opened causes the dialog controls to be updated in plain
+	   * sight - a rather visible and eye-catching affair once you are aware of it.
+	   * Updating the dialog controls manually before switching to the active page
+	   * causes these updates to be done while the user cannot see it. -JW
+	   */
+	  GetPage(dwPage)->UpdateDialogControls(this, false);
 	  SetActivePage(dwPage);
+  }
 	UnlockWindowUpdate();
 
 	// Prevent losing the focus when invoked by keyboard