Have a very simple workflow with 2 sequential actions. Open it and click on Edit.
For both of the actions, click on its upper right corner (the gears on blue background) to open their prefs.
For both of the actions, click on its upper right corner (the small blue triangle pointing to the left) to close their prefs.
Only the prefs window that was opened last closes, the other one stays open.
So, actually, if you opened Action1, the opened Action2, and then try to close Action1, it's Action2 that closes.
Expected: Each close button should close its corresponding Prefs box. Alternatively, there should only be 1 open at a time, opening one should close all the others.