After upgrade from Leap 15.0 to 15.1, Autohiding Panel now oscillates/flashes

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1

I have my panel configured to autohide. After the upgrade, it now seems to oscillate or “flash” randomly. By this I mean it unhides and rehides repeatedly, without stopping. In autohide mode, it should normally stay hidden unless the cursor approaches it. If I go to the panel and fiddle with it, it will stop oscillating, but then it soon starts oscillating again in a short time.

I’m using KDE:

KDE Plasma Version 5.12.8
KDE Frameworks Version 5.55.0
Qt Version: 5.9.7
Kernel Version: 4.12.14
OS Type: 64 bit

Is this some kind of new “feature” that I can disable, or a bug? Has anyone else seen it?

2

Try with a different user

3

There was a bug a while back where that occurred…

376065 – auto-hide panel flickers

… although that report is still open I thought it had been fixed.

4

I think I remember seeing that in a virtual machine where I upgraded. I’m not sure what I did to fix it, and I have since deleted that virtual machine.

My vague recollection was that I turned off auto-hide, logged out and logged in again, then turned on auto-hide.

My practice for a long time has been to use auto-hide for the panel, and to switch the menu to the launcher based on cascading popup menus.

I’m finding that I can no longer do that. I have to switch the menu first before I turn on auto-hide. The system where I had the problem that you describe, was one where I had turned on auto-hide first and switched the menu style later. And I’m guessing that’s why it happened.

5

I don’t immediately see the problem with a new user I add, but how does that solve my problem? I don’t want to throw away all my configuration.

6

If it works for a different user then something is amiss in you normal user’s configuration.

Maybe try nrickert’s suggestion. ie turn it off log out back in then turn on again. That might reset the misbehaving config

7

Already tried that. No Joy.

As far as something being “amiss,” it worked fine in all previous OpenSUSE versions, most recently in 15.0, so they’ve broken backcompat somehow here in a very nasty way.

8

Well config file structures can change so sometimes it is best to just wipe them and recreate the desktop. You will find the plasma*rc files in the ~/.config directory. If you have done upgrades over multiple versions these things can pile up eventually something breaks. Since it works for different user it is most definitely a problem in your home.

Not probably best to cleanout ~/.cache also

9

I remember testing some industrial Siemens touch-panel PCs in a lab once; the effect was with Windows NT, though, and the Windows task bar on auto-hide. (Officially, WinNT didn’t have USB drivers, but Siemens had some developed specifically for those PCs. The driver sometimes generated activity at the bottom-left screen edge which made the task bar oscillate.)

Are you using some kind of touch-sensitive screen or Wacom-style tablet? KDE comes with support for those (see KDE System Settings → Workspace → Desktop Behavior → Touch Screen, also under Personalisation → Accessibility → Activation Gestures, also Hardware → Input Devices → Touchpad, and finally in Startup and Shutdown → Background Services → Startup Services → Touchpad). You may try disabling some of those options; I have done so. My panel is on auto-hide on the top of the screen.

My reasoning is that your KDE may think there’s a device other than your mouse spuriously triggering an action at (0,0) on the screen. Maybe there’s also something going on with triggering on screen edges (Workspace → Desktop Behavior → Screen Edges). Are you able to move the panel from its current location to another screen edge?

10

I said above that when I add a new user, I don’t see the issue. So the assumption was it was KDE-config-related. However, today I tried moving ~/.config away, which I believe contains all of my user KDE config. After I restart plasmashell, the desktop appearance reverts to Leap 15.1 default, the same as the new user, *but the problem still happens!
*
So apparently, the reason it doesn’t happen with a new user is related to the apps being run. I suppose certain apps have to be open for it to reproduce. I’m not running anything exotic - X apps konsole, xterm, emacs, KDE System Monitor. As far as processes with no window, some tomcat servers and openvpn.

This leads back to my unanswered question. Is there some sort of a “attention getting” feature of certain apps like konsole that is expected to unhide the panel and hilite the affected panel button? Like on Windows, an app can cause your task bar to show itself and the related button to flash.

If this feature exists, how do I disable it globally for the panel? I don’t see anything obvious in the panel “more settings” GUI.

11

Some of the KDE configuration might be in “.local/share/”

12

Also clear ~/.cache

13

Sorry, I didn’t catch that the first time. If other users don’t show this panel-oscillating behavior, the brute-force (but laborious) way to investigate further would be to copy Plasma-/KDE related config files one by one, log out and in each time and observe the changes. Not very tempting.

I know not of such a feature. But if there is one, maybe it’s detectable using dbus-monitor; run it in an xterm/konsole while testing:

$ **dbus-monitor** 
signal time=1560500774.903448 sender=org.freedesktop.DBus -> destination=:1.42 serial=4 path=/org/freedesktop/DBus; interface=org.freedesktop.DBus; member=NameLost
   string ":1.42"
signal time=1560500820.396653 sender=:1.15 -> destination=(null destination) serial=543 path=/component/kwin; interface=org.kde.kglobalaccel.Component; member=globalShortcutPressed
   string "kwin"
   string "Walk Through Windows"
   int64 912097

Further candidates for interesting messages being logged, additionally to dbus-monitor:

  • journalctl
    -f -b --no-hostname --output=short-unix
  • dmesg
    -dT -w
  • tail -f .xsession-errors
    /var/log/Xorg.0.log
    Chances are that at least one of those logs floods your terminal while the panel-flashing occurs. That could be the one containing further hints. Post some of the output here, using the CODE tags (#).