undo does not work properly with classifier associations

In the trunk version, no error is raised when undoing. Only deletion of the association results in the association ends (Properties) being shown as attributes, instead of being deleted.

Looks like Property.owningAssociation is not set. Therefore there is no composite relation between the property and association object, hence it is not removed as soon as the association is removed.

Indeed the 0.12 code is less predictable. It will be a tough job to trace that down.

There is still an issue with associations and undo. This is a more general problem that also occurs with line-like relationship objects:

• create two classes/interface/actions
• Create a relationship between those two
• delete the relationship with bs or del
• undo (ctrl-z)

This will cause the relationship to appear as expected, only the handles at the end are not connected. Note that the relationship is made on model level though.

This probably has something to do with when a handle is disconnected. This should be done before the relationship itself is removed from the canvas.

(In [2214]) * incremented version to 0.3.5

• made Item.canvas read-only (can be set by calling Canvas.add() and Canvas.remove())
• fixed unit tests
• looks like this is a fixes #95

Seemed like it was an issue in Gaphas after all. By making the item-canvas connection protocol stricter it was possible to remove @observed from the Item.canvas setter.