--- generic/tkPack.c.orig	2009-09-20 14:40:30.000000000 -0300
+++ generic/tkPack.c	2009-09-20 15:10:34.000000000 -0300
@@ -585,11 +585,24 @@
 
     /*
      * If the master has no slaves anymore, then don't do anything at all:
-     * just leave the master's size as-is.
+     * just leave the master's size as-is, but signal the master with the
+     * <<GeometryManager>> virtual event.
+     * Otherwise there is no way to "relinquish" control over the master
+     * so another geometry manager can take over.
      */
 
     if (masterPtr->slavePtr == NULL) {
-	return;
+        union {XEvent general; XVirtualEvent virtual;} event;
+        memset(&event, 0, sizeof(event));
+        event.general.xany.type = VirtualEvent;
+        event.general.xany.serial = NextRequest(Tk_Display(masterPtr->tkwin));
+        event.general.xany.send_event = False;
+        event.general.xany.window = Tk_WindowId(masterPtr->tkwin);
+        event.general.xany.display = Tk_Display(masterPtr->tkwin);
+        event.virtual.name = Tk_GetUid("GeometryManager");
+        Tk_HandleEvent(&event.general);
+
+        return;
     }
 
     /*
--- generic/tkGrid.c.orig	2009-09-20 14:40:16.000000000 -0300
+++ generic/tkGrid.c	2009-09-20 15:09:34.000000000 -0300
@@ -1703,13 +1703,24 @@
 
     /*
      * If the master has no slaves anymore, then don't do anything at all:
-     * just leave the master's size as-is. Otherwise there is no way to
-     * "relinquish" control over the master so another geometry manager can
-     * take over.
+     * just leave the master's size as-is, but signal the master with the
+     * <<GeometryManager>> virtual event.
+     * Otherwise there is no way to "relinquish" control over the master
+     * so another geometry manager can take over.
      */
 
     if (masterPtr->slavePtr == NULL) {
-	return;
+        union {XEvent general; XVirtualEvent virtual;} event;
+        memset(&event, 0, sizeof(event));
+        event.general.xany.type = VirtualEvent;
+        event.general.xany.serial = NextRequest(Tk_Display(masterPtr->tkwin));
+        event.general.xany.send_event = False;
+        event.general.xany.window = Tk_WindowId(masterPtr->tkwin);
+        event.general.xany.display = Tk_Display(masterPtr->tkwin);
+        event.virtual.name = Tk_GetUid("GeometryManager");
+        Tk_HandleEvent(&event.general);
+
+        return;
     }
 
     if (masterPtr->masterDataPtr == NULL) {
