I have noticed designer overwrite properties when moving from one timerboundaryevent to another, this is.
0. I have TimerBoundaryEvent1 with a Time Duration and TimerBoundaryEvent2 with Time Cycle set 1. I click on TimerBoundaryEvent1 and I see Time Duration for it 2. I click on TimerBoundaryEvent2 and Time Duration is not erased but also set for TimerBoundaryEvent2 3. I go back to TimerBoundaryEvent1 and now both TimerBoundaryEvents have both Time Duration and Time Cycle set which is not supposed to happen.
Also trying to move a TimerBoundaryEvent position will throw a "unhandled event loop exception" on ecliipse, I guess is designed not to be moved once attached to a task, but when I move the task it is attached TimerBoundaryEvents stays on the same position making the diagram to look confusing.
for the problem with moving the boundary events when moving the subprocess or call activity, I attached a patch to ACT-986. Maybe this will be resolved in 5.9 🙂