Comment 4 for bug 1512002

I recently installed 2 machines with Xubuntu 15.10 and I see this issue very often, but not *always* on one of them (a desktop PC) and never on the other (a laptop).

On the desktop machine, I simply hover over the dialog and hold my ESC key down until it eventually goes away. Like another responder said, it seems to be time dependent and stores the events while the machine is locked. Typically takes a few seconds (so probably 30-40 cancellations of the dialog) but the most recent one took over a minute (I'd estimate the dialog re-appeared a couple of hundred times at least) although the machine wasn't locked for significantly longer than before.

Once it disappears for the last time, it seems to stay away until the next time the machine is locked/unlocked.

It's parent process is the xfce-session (in my case) so it's not obvious what is actually triggering it to appear. Entering the password seemingly makes no difference to the persistent nature of the dialog.