Index: src/glyphs.c
===================================================================
RCS file: /usr/CVSroot/XEmacs/xemacs/src/glyphs.c,v
retrieving revision 1.23.2.65
diff -u -r1.23.2.65 glyphs.c
--- src/glyphs.c 2000/05/04 16:04:17 1.23.2.65
+++ src/glyphs.c 2000/05/09 11:23:12
@@ -4245,6 +4245,23 @@
     }
 }
 
+/* Unmap and remove all instances from the frame cache. */
+void
+reset_frame_subwindow_instance_cache (struct frame* f)
+{
+  Lisp_Object rest;
+
+  LIST_LOOP (rest, XWEAK_LIST_LIST (FRAME_SUBWINDOW_CACHE (f)))
+    {
+      Lisp_Object value = XCAR (rest);
+      /* Make sure that the subwindow is unmapped so that window
+	 deletion will not try and do it again. */
+      unmap_subwindow (value);
+      XWEAK_LIST_LIST (FRAME_SUBWINDOW_CACHE (f))
+	= delq_no_quit (value, XWEAK_LIST_LIST (FRAME_SUBWINDOW_CACHE (f)));
+    }
+}
+
 /*****************************************************************************
  *                              subwindow exposure ignorance                    *
  *****************************************************************************/
Index: src/glyphs.h
===================================================================
RCS file: /usr/CVSroot/XEmacs/xemacs/src/glyphs.h,v
retrieving revision 1.18.2.46
diff -u -r1.18.2.46 glyphs.h
--- src/glyphs.h 2000/05/03 14:47:10 1.18.2.46
+++ src/glyphs.h 2000/05/09 11:23:15
@@ -1055,6 +1055,7 @@
 Lisp_Object image_instance_parent_glyph (struct Lisp_Image_Instance*);
 int image_instance_changed (Lisp_Object image);
 void free_frame_subwindow_instance_cache (struct frame* f);
+void reset_frame_subwindow_instance_cache (struct frame* f);
 
 struct expose_ignore
 {
Index: src/window.c
===================================================================
RCS file: /usr/CVSroot/XEmacs/xemacs/src/window.c,v
retrieving revision 1.41.2.49
diff -u -r1.41.2.49 window.c
--- src/window.c 2000/05/05 19:43:41 1.41.2.49
+++ src/window.c 2000/05/09 11:23:34
@@ -5212,6 +5212,11 @@
 
       mark_windows_in_use (f, 1);
 
+      /* Force subwindows to be reinstantiated. They are all going
+         anyway and if we don't do this GC may not happen between now
+         and the next time we check their integrity. */
+      reset_frame_subwindow_instance_cache (f);
+
 #if 0
       /* JV: This is bogus,
 	 First of all, the units are inconsistent. The frame sizes are measured
@@ -5354,6 +5359,13 @@
 	  w->hscroll = p->hscroll;
 	  w->modeline_hscroll = p->modeline_hscroll;
 	  w->line_cache_last_updated = Qzero;
+	  /* The subwindow instance cache isn't preserved across
+	     window configurations, and in fact doing so would be
+	     wrong. We just reset to zero and then redisplay will fill
+	     it up as needed. */
+	  w->subwindow_instance_cache = make_lisp_hash_table (30,
+							      HASH_TABLE_KEY_WEAK,
+							      HASH_TABLE_EQ);
 	  SET_LAST_MODIFIED (w, 1);
 	  SET_LAST_FACECHANGE (w);
 	  w->config_mark = 0;