Deleting Associations

Hi!

I have a problem using Umbrello (1.3.2) : In a class-diagram, I create two
classes and connect them with an association. After that, I delete the
association (using right-click-context.menu). Okay, the association is now
gone.
Now I remove one of the two classes from the class diagram and re-inserts it
from the treeview. Now that association I just deleted is visible again.

How can I delete an association totally from Umbrello so that it is
completely gone?
(I have created an association by accident in my quite complex project and
want to remove it but I can't... I even tried to remove it from
XML-Source...)

Christian Caroli