Saw problem again today. Opened music app. Could move it behind sidebar which was inactive. I then 'clicked through' the sidebar and closed the app. Opened the app again: same problem was there. Opened a second app. (a terminal) and this app. move the terminal into autohide .... The problem dies not depend on a particular app. being used. I've seen it now with three apps.
Saw problem again today. Opened music app. Could move it behind sidebar which was inactive. I then 'clicked through' the sidebar and closed the app. Opened the app again: same problem was there. Opened a second app. (a terminal) and this app. move the terminal into autohide .... The problem dies not depend on a particular app. being used. I've seen it now with three apps.