Too easy to delete a custom reference

[sellig]

I am using custom references to link my BPMN diagrams backward. This allows anyone in the project to open a BPMN diagram and being able to locate its parent easily. I have set out a modeling rule where the custom reference is set up on the start event of the child diagram to its parent. It works fine for my project...

However, there is a snag: it is too easy to delete a custom reference:
- The custom reference can be deleted even if the user doesn't have a lock on either of the diagrams (I am using SVN as version control)
- There is no confirmation message shown to the user before the delete is performed!
- The delete button is between other popular functions on that screen and could be pressed easily by mistake.

Surprisingly, it is harder to set-up a custom reference since you need to have a lock on the diagrams!

Is there a way to better protect the custom references from unintentional deletions?

I think that the custom reference function that you provide is very important: there should be a way to navigate your models in the hierarchy up or down. CTRL+K provides this function for navigating down and custom references can provide it to navigate your models up in the hierarchy provided that you take the time to set them up. When people access models in a support function rather than a design function, they can access a model anywhere in the hierarchy. It should be easy for them to navigate up of down the model hierarchy without being as familiar with the categorization of the models as the designers are.