Saving of aspect does not work after removing a reuse of an Association concern

[Omar Alam]

I found this case when I reused Association concern from Association end, then removed the Association reuse, and then tried to save the aspect. It throws an exception because the Association end still contain references to COREModel.

[Céline Bensoussan]

The reuse of the Association Concern will not be shown in the reuses container so it will not be possible to remove the reuse from there. It should be removed by changing the multiplicity back to 1.