Index: generic/xotclStack.c
===================================================================
diff -u -red8301802df5fc7427fc0e4dbd82c2cf880329de -r26a70d9d268d8d827ec0ed631549fa6c5217d832
--- generic/xotclStack.c	(.../xotclStack.c)	(revision ed8301802df5fc7427fc0e4dbd82c2cf880329de)
+++ generic/xotclStack.c	(.../xotclStack.c)	(revision 26a70d9d268d8d827ec0ed631549fa6c5217d832)
@@ -34,6 +34,37 @@
   return cs->top;
 }
 
+XOTclCallStackContent *
+XOTclCallStackFindLastInvocation(Tcl_Interp *interp, int offset) {
+  XOTclCallStack *cs = &RUNTIME_STATE(interp)->cs;
+  register XOTclCallStackContent *csc = cs->top;
+  int topLevel = csc->currentFramePtr ? Tcl_CallFrame_level(csc->currentFramePtr) : 0;
+  int deeper = offset;
+
+  /* skip through toplevel inactive filters, do this offset times */
+  for (csc=cs->top; csc > cs->content; csc--) {
+    /* fprintf(stderr, "csc %p callType = %x, frameType = %x, offset=%d\n",
+       csc,csc->callType,csc->frameType,offset); */
+    if ((csc->callType & XOTCL_CSC_CALL_IS_NEXT) ||
+        (csc->frameType & XOTCL_CSC_TYPE_INACTIVE))
+      continue;
+    if (offset)
+      offset--;
+    else {
+      /* fprintf(stderr, "csc %p offset ok, deeper=%d\n",csc,deeper); */
+      if (!deeper || cs->top->callType & XOTCL_CSC_CALL_IS_GUARD) {
+        return csc;
+      }
+      if (csc->currentFramePtr && Tcl_CallFrame_level(csc->currentFramePtr) < topLevel) {
+        return csc;
+      }
+    }
+  }
+  /* for some reasons, we could not find invocation (topLevel, destroy) */
+  /* fprintf(stderr, "csc %p could not find invocation\n",csc);*/
+  return NULL;
+}
+
 static void 
 CallStackClearCmdReferences(Tcl_Interp *interp, Tcl_Command cmd) {
   XOTclCallStack *cs = &RUNTIME_STATE(interp)->cs;