I have deleted a menu entry "Delete rule" with

del  M[Delete rule]

According to the documentation the pushbutton "Delete rule" in the toolbar should now vanish as well. But it is still there. What could be the reason?

In this transaction, the menu item "Delete rule" invokes the function code DELE. For some reason the toolbar button "Delete rule" invokes the function code DELL. So GuiXT assumes that these are different functions.

Solution:

Please use

del  M[Delete rule]

del  P[Delete rule]