Index: generic/xotclStack.c
===================================================================
diff -u -r2198228db95e35c248720652c69f53a21eb718e6 -r117b5c8c5af22d5bb38fdb68b5fbd8963f18c697
--- generic/xotclStack.c	(.../xotclStack.c)	(revision 2198228db95e35c248720652c69f53a21eb718e6)
+++ generic/xotclStack.c	(.../xotclStack.c)	(revision 117b5c8c5af22d5bb38fdb68b5fbd8963f18c697)
@@ -145,6 +145,26 @@
   return NULL;
 }
 
+/*
+ * check, if there is an active filters on "obj" using cmd
+ */
+XOTCLINLINE static int
+FilterActiveOnObj(Tcl_Interp *interp, XOTclObject *obj, Tcl_Command cmd) {
+  XOTclCallStack *cs = &RUNTIME_STATE(interp)->cs;
+  XOTclCallStackContent *bot = cs->content;
+  register XOTclCallStackContent *csc = cs->top;
+  while (csc > bot) {
+    /* only check the callstack entries for this object &&
+       only check the callstack entries for the given cmd */
+    if (obj == csc->self && cmd == csc->cmdPtr &&
+        csc->frameType == XOTCL_CSC_TYPE_ACTIVE_FILTER) {
+      return 1;
+    }
+    csc--;
+  }
+  return 0;
+}
+
 static void 
 CallStackClearCmdReferences(Tcl_Interp *interp, Tcl_Command cmd) {
   XOTclCallStack *cs = &RUNTIME_STATE(interp)->cs;