Think I discovered a bug in SU 2015. I had a group selected and I did a “hide dialogs” and then “show dialogs” and SU seemed to perform a “soften edges” on the group. I only noticed because some softened lines showed up, so I moused over the undo button and it read “Undo Soften Edges”.
For now, I just have to remember to have nothing selected when I show/hide dialogs.
What OS? I haven’t been able to reproduce this on my Mac. What you describe is as if somehow the hide/show dialog sequence generated a click in the soften edges dialog.
This is a quite old bug if it is the same one I remember. I also can not reproduce it but have seen it at least once in version 15, but I don’t think it it happened when using hide/show dialogs because I almost never use it.