Fix crash clicking desktop during setup (NULL pointer was unchecked)

reactos/subsys/win32k/ntuser

diff -u -r1.26 -r1.27
--- focus.c	25 Nov 2004 22:18:59 -0000	1.26
+++ focus.c	19 Dec 2004 11:05:48 -0000	1.27
@@ -16,7 +16,7 @@

  * along with this program; if not, write to the Free Software
  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  *

- * $Id: focus.c,v 1.26 2004/11/25 22:18:59 navaraf Exp $

+ * $Id: focus.c,v 1.27 2004/12/19 11:05:48 tamlin Exp $

  */
 
 #include <w32k.h>

@@ -238,12 +238,18 @@

   if (Top != Window->Self)
     {
       TopWindow = IntGetWindowObject(Top);

+      if (TopWindow == NULL)
+        {
+          SetLastWin32Error(ERROR_INVALID_WINDOW_HANDLE);
+          return FALSE;
+        }

     }
   else
     {
       TopWindow = Window;
     }
 

+  /* TMN: Check return valud from this function? */

   IntSetForegroundAndFocusWindow(TopWindow, Window, TRUE);
 
   if (Top != Window->Self)