Direct edit on "end" element can lead to make it disappear from its "ends" compartment

On a `ConnectionDefinition` (or any graphical node with the _ends_ compartment, in the _ends_ compartment, rename an _end_ (through direct edit) without putting the keyword _end_ make disappear the _end_ of the compartment because it removes the _end_ property of the associated _ReferenceUsage_/_PortUsage_