steps to reproduce: 1) Run some QT apps which are using systray (opera, kadu) 2) Start toggling composting: xfconf-query -c xfwm4 -p /general/use_compositing Effect: many glitches and disappears of qt tray icons FYI Toggling is needed for playing movies with proper VBlank on nvidia binary blob
Created attachment 5324 PANEL_DEBUG=systray log This is still an issue with version 4.10.1. I've attached a panel log file created with 2 vlc instances running while toggling the compositor on and off. In the log file I've annotated what exactly happened to tray icons at the switches. To summarize: Switching the compositor on and off may result in apparent or complete disappearing of the tray icon of certain applications (mainly qt). The console output of those application is: X Error: BadMatch (invalid parameter attributes) 8 Major opcode: 2 (X_ChangeWindowAttributes) Resource id: 0x340001b In some cases the application needs to be restarted to get the tray icon back. I've had also cases of apparent disappearance of tray icons without compositor state change, which may be related to this issue (although hard to reproduce).
I can confirm, same issue here.
This is still an issue with panel 4.14.0. When the panel is (re)started while QT apps are running, they will not re-appear in the systray. If the compositor is toggled while they are running, they will disappear.
Furthermore, the only way to make a vanished app reappear in the systray is to restart it. Possible test candidates (verified to disappear) are: KeepassXC, Owncloud desktop client
While all of the above is true, there's not much we can do about it. Plus the notification area is considered deprecated upstream so we would have to fork this part of Gtk to be able to improve things (full disclosure: we won't do that).
*** Bug 11019 has been marked as a duplicate of this bug. ***
*** Bug 12082 has been marked as a duplicate of this bug. ***