=== modified file 'src/frame.c'
*** src/frame.c	2012-01-19 07:21:25 +0000
--- src/frame.c	2012-02-22 10:43:37 +0000
***************
*** 935,940 ****
--- 935,949 ----
       forever.  Forestall that.  */
    CHECK_LIVE_FRAME (frame);
  
+   passed = 0;
+   for (tail = Vframe_list; CONSP (tail); tail = XCDR (tail))
+     if (EQ (frame, XCAR (tail)))
+       passed++;
+ 
+   if (passed == 0)
+     abort ();
+ 
+   passed = 0;
    while (1)
      for (tail = Vframe_list; CONSP (tail); tail = XCDR (tail))
        {