Bug 346638 was closed, but the problem persists in Plasma 5.8.6 from openSuse. That is, when focus moves from one window to another the auto-hide panel pops up and stays, covering the bottom of other windows, until a mouse-over on the panel. The panel won't hide when Spectacle is in use for a xcreen capture or when the net manager icon is expanded into the net manager panel Today the main panel also refuses, sometimes, to hide when I mouse-over. On a galactic scale this is a minor bug, but still annoying. I'm happy to provide more details or try test cases.
This should have finally been resolved by [1]. Feel free to re-open if the issue persists after this.
[1] https://cgit.kde.org/kwin.git/commit/?id=c0b207a2b524b720e54cd583a225b0681ab6e2b2
The problem still exists in Kubuntu 20.04 (Plasma 5.18.5), as well as in Kubuntu 18.04. It is very annoying. Would you consider fixing this, eventually?
Reading a thread in KDE forum (https://forum.kde.org/viewtopic.php?t=132342), I just found a way to prevent this problem, in my case: Set 'Hide utility windows for inactive applications' in settings:/workspace/windowmanagement/ -> tab 'Advanced'. [I am using 'Click to focus' for 'Window activation policy'.]
That means your issue is Bug 468356, which means that the original issue really was fixed as Kai mentioned. :) In the future please submit a new bug report when you have an issue that looks like an old and already resolved one. Thanks!
Please, don't be rude. Replying to me after 1 year and 7 months and when Kubuntu 20.04 has been largely surpassed/replaced by 22.04 is already impertinence. The bug you suggest (468356) has the description "when you move the mouse focus away from the panel, it stays visible", which is not the case with my bug. My bug does what is described here: "when focus moves from one window to another the auto-hide panel pops up and stays, covering the bottom of other windows, until a mouse-over on the panel". Having that out of the way, the same bug is _still_ a problem in Kubuntu 22.04 (KDE Plasma version 5.18.8). Please, stop evading this bug and deal with it!
> Having that out of the way, the same bug is _still_ a problem in Kubuntu > 22.04 (KDE Plasma version 5.18.8). Sorry to be back about this, but to be very clear, I really doubt the commit above ([1]), from 2017, has not reached KDE Plasma version 5.18.8. If that is truly the case, that commit _did not_ correct the bug. And, please, don't close this bug as fixed, without filling "Version fixed in".