SUMMARY When closing the player on screen 1, then opening it on screen 2, Full screen will jump to screen 1 until the player is moved. STEPS TO REPRODUCE 1. Open and move Haruna to screen 1. 2. Close Haruna. 3. Open Haruna on screen 2. (I do this via opening a video in Dolphin on screen 2) 4. Do no move the player window. 5. Full screen the player via F or double clicking. OBSERVED RESULT Haruna is full screen on screen 1. EXPECTED RESULT Haruna is full screen on screen 2. SOFTWARE/OS VERSIONS Linux/KDE Plasma: Linux hostname 6.16.10-arch1-1 #1 SMP PREEMPT_DYNAMIC Thu, 02 Oct 2025 19:26:36 +0000 x86_64 GNU/Linux KDE Plasma Version: 6.4.5 KDE Frameworks Version: 6.18.0 Qt Version: 6.9.2 ADDITIONAL INFORMATION After exiting full screen once, the player behaves as expected.
I neglected to mention that this is under kwin/wayland. I also have this bizzare finding: I can fix this issue by lowering the "width" and "height" properties of ApplicationWindow in Main.qml. This may affect your abillity to reproduce the issue. the default of 1000x600: breaks 1000:1000: breaks 800:800: works 500x300: works So, my best guess is that somewhere deep in Qt/QML there is a branch for how close the non-fullscreen buffer is to the one required for fullscreen, and then some kind of divergence between the code paths causes the bug. However, I have not managed to make a minimal QML reproduction in order to turn this into a QT bug report, so there may be other factors. This could mean that these values are also specific to your monitor resolution(s). I'm using two 1080p Displays here.