Description Peter Cigehn 2016-10-14 10:45:21 EDT

The activity frame currently have a very small margin to the top and left borders of the diagram itself. So whenever the activity frame is selected, either intentionally or, probably more often, unintentionally when the user "misses" any of the contained elements, like actions or flows, the complete activity "jumps" on the screen when the selection handles are displayed on the frame. This also causes both a vertical and horizontal scrollbar to appear.

This "jumping" is extremely annoying, and stressing on the eye, especially when you by mistake selects the activity frame itself, which happens whenever you click somewhere inside it.

Steps to reproduce:

1) Create a UML model with an activity diagram
2) Open the activity diagram and select the activity frame by clicking inside it
3) Observe how the complete activity frame, including its contents, "jumps" away slightly downwards and to the right, to make room for the selection handles.
4) Create an action in the activity and make the action selected
5) Observe how the activity frame "jumps back" again.

I guess that by making the margin to the top and left borders would make the "jumping" effect to disappear, to ensure that the selection markers gets enough room. It should of course be considered the case when you add a parameter node to the left border as well, since the same kind of "jumping" effect can be seen whenever a parameter node is selected as well. For some reason it it seem to be impossible to place an parameter node on the top border. But if it would have been possible then I guess the same kind of "jumping" effect would have been seen for this case as well.