Checking for a window before we try to refer to it (see e-mail by Eero Pajarre dated 1/10/2010 at 2:48 PM).

git-svn-id: https://svn.code.sf.net/p/freeglut/code/trunk@870 7f0cb862-5218-0410-a997-914c9d46530a

freeglut/freeglut/src/freeglut_main.c

@@ -1590,6 +1590,8 @@ LRESULT CALLBACK fgWindowProc( HWND hWnd, UINT uMsg, WPARAM wParam,
     /* printf ( "Window %3d message <%04x> %12d %12d\n", window?window->ID:0,
              uMsg, wParam, lParam ); */
 
+    if ( window )
+    {
       /* Checking for CTRL, ALT, and SHIFT key positions:  Key Down! */
       if ( !lControl && GetAsyncKeyState ( VK_LCONTROL ) )
       {
@@ -1699,7 +1701,7 @@ LRESULT CALLBACK fgWindowProc( HWND hWnd, UINT uMsg, WPARAM wParam,
 
           rAlt = 0;
       }
-
+    }
 
     switch( uMsg )
     {