KDE doesn't allow a window to stretch fullscreen over both monitors. If I try, I get a vncviewer window with the geometry 1920x1200 but a session with 3520x1200. Any window can manually be resized to stretch over both monitors. If I maximize a window which is placed such that it's seen partly on both monitors it will only maximize on the monitor which was displaying the the largest part. I am not surprised that this wierd behaviour by KDE breaks the ThinLinc client's multihead functionality. It seems that KDE have historically had options to allow fullscreen stretching over multiple monitors: "Enable multiple monitor window fullscreen support" & "Enable multiple monitor window maximize support" in System Settings > Display > Multiple Monitors But this seems to be gone in new versions of KDE. See: http://blog.martin-graesslin.com/blog/tag/scripting/ > KWin had the functionality to disable multiscreen support for fullscreen windows and that really cluttered both code and UI. And it just did not make any sense. There are just no valid usecases to have in general fullscreen windows span all screens, except for video walls.
Someone here indicates that it could be possible to extend the "Video Wall" script for a generic application: https://forum.kde.org/viewtopic.php?f=111&t=107629
This has been reported to be an issue in KDE on Ubuntu 14.04. I reproduced it in KDE 4.14.6 on Fedora 20. Bug 5182 comment #13: > From ThinLinc client point of view, multi-monitor is only fully supported if > the window manager supports EWMH and the properties; _NET_WM_ACTION_FULLSCREEN, > _NET_WM_STATE_FULLSCREEN and _NET_WM_FULLSCREEN_MONITORS At least in KDE 4.14.6 on Fedora 20; xprop -root | grep _NET_WM_ACTION_FULLSCREEN xprop -root | grep _NET_WM_STATE_FULLSCREEN xprop -root | grep _NET_WM_FULLSCREEN_MONITORS all three are found.
The "Video Wall" script does indeed work. What you need to do is: * Open the window manager settings * Select "KWin Scripts" * Enable "Video Wall" * Open the settings for the script and add "thinlinc-client" to the list of applications (this is the WM_CLASS of the client) After that fullscreen over all monitors works. However it still ignores _NET_WM_FULLSCREEN_MONITORS, so you can't get fullscreen over a single window after this.
Filed an upstream bug: https://bugs.kde.org/show_bug.cgi?id=394246
(In reply to comment #4) > The "Video Wall" script does indeed work. What you need to do is: > Tested on Fedora 27 with KWin 5.12.4.
(In reply to Pierre Ossman from comment #4) > The "Video Wall" script does indeed work. What you need to do is: > > * Open the window manager settings > * Select "KWin Scripts" > * Enable "Video Wall" > * Open the settings for the script and add "thinlinc-client" to the list of > applications (this is the WM_CLASS of the client) > > After that fullscreen over all monitors works. > > However it still ignores _NET_WM_FULLSCREEN_MONITORS, so you can't get > fullscreen over a single window after this. Depending on your KDE version, the configuration of the "Video Wall"-script might not be available from the "KWin Scripts" page. It's unclear to where these settings have been moved.
This was tested as part of bug 7006, comment 46, and the multihead handling on KDE seems to have been fixed since last time it was tested. I used 3 monitors and could run the the ThinLinc client in fullscreen on all monitors. Tested on Fedora 33 with KDE Plasma 5.20.
