{tree}:erase and selections

[Guido.Bosch@loria.fr (Guido Bosch)]

Using the function {tree}:erase on selected trees seems to be
disastrous for the pretty printer of a ctedit:

** sun4 : machine error : segmentation fault

Is there a function that does the same by taking care about
selections, or, if not so, how can I deselect all possible selection
before doing `{tree}:erase' (the function that is called by
the menu "Selections" -> "Clear all" would do).

Thanks for any help.	

	Guido