When I check the option in the taskbar "Show only task from the current screen" option, my plasma task bar only shows the window in the other screen. When I move a window (for example kwrite) to the other screen, its option appears in the menu. Video attached so you can see the behaviour: https://youtu.be/U1VL31tUB_w Note: Using ubuntu 15.04 with KDE Frameworks Version 5.9.0. My screen layout is that the primary screen is at the bottom and the second screen is at the top.
I have 3 monitors and this happened "randomly" for me in Plasma 5.5.5, maybe because plasmashell starts before all monitors are detected. However, restarting plasmashell would solve the problem. Now, in Plasma 5.7.5, that still happens, but restarting plasma doesn't quite fix it anymore. The primary screen (center monitor) is fine. But the panel on the left monitor shows the windows in the right monitor. And the panel on the right monitor shows the windows on the left monitor. This is 100% consistent, no matter how many times I restart plasmashell or the entire system.
This happens in 5.9.1 every time I connect an external monitor. After reboot the issue disappears. Disconnecting monitor makes taskbar not show any windows at aall.
I installed Plasma 5.8.5 (Kubuntu PPA for Ubuntu 16.10) and the problem I described in comment 1 is completly solved. I didn't test Plasma 5.9.x though. I tried to reproduce comment 2 by disconnecting and connecting a monitor and it happened as described. However, a lot of non-Plasma-related side effects happened: kcm_kscreen crashed everytime I tried to open it, dpi config got messed up and xrandr gave errors when tried to change it. Restarting X fixed it.
Hello! This bug report was filed for KDE Plasma 4, which reached end-of-support status in August 2015. KDE Plasma 5's desktop shell has been almost completely rewritten for better performance and usability, so it is likely that this bug has already been resolved in Plasma 5. Accordingly, we hope you understand why we must close this bug report. If the issue described here is still present in KDE Plasma 5.12 or later, please feel free to open a new ticket in the "plasmashell" product after reading https://community.kde.org/Get_Involved/Bug_Reporting If you would like to get involved in KDE's bug triaging effort so that future mass bug closes like this are less likely, please read https://community.kde.org/Get_Involved#Bug_Triaging Thanks for your understanding! Nate Graham
Heu, Just tested on KDE Plasma 5.12.4 and its indeed resolved.