Created attachment 124004 [details] video demonstration SUMMARY After recent plasma upgrate kcolorchooser show colors from first display on same coordinates even if cursor placed somewhere on a second display. Please see attached video for demonstration. SOFTWARE/OS VERSIONS Kcolorchooser version: 19.08.3 KDE Plasma Version: 5.17.3 KDE Frameworks Version: 5.64.0 Qt Version: 5.13.2 System: Arch linux, 2 lg ultra hd displays
Update: it's not colors from first display, it's just random colors presented on screen.
I can confirm this behaviour on my setup as well. KColorChooser works all fine on my leftmost display but the results seem to be random on others. System: Arch Linux Driver: Nvidia proprietary 440.36-2 Display layout: ┌----------------┐┌--------------------------┐┌------------------┐ | 1920x1080 DP-0 || || 1920x1080 HDMI-0 | └----------------┘| 3840x2160 DP-3 |└------------------┘ | | └--------------------------┘ xrandr: xrandr --fb 11520x2160 \ --output DP-0 --auto --scale 2.0 --dpi 256 --panning 3840x2160+0+0 --pos 0x0 \ --output DP-3 --auto --primary --scale 1.0 --dpi 163 --panning 3840x2160+3840+0 --pos 3840x0 \ --output HDMI-0 --auto --scale 2.0 --dpi 205 --panning 3840x2160+7680+0 --pos 7680x0
I noticed that again this is somehow related to global scale and using: QT_AUTO_SCREEN_SCALE_FACTOR=0 QT_SCALE_FACTOR=0.5 kcolorchooser ...resolves the issue (of 'cos you get super small UI on HiDPI displays tho, and the QT_SCALE_FACTOR needs to be adjusted based on your global scale setting). This reminds me another issue (bug 413577) I reported, where it could also be 'resolved' by disabling scaling for affected apps. I guess these problems may have the same root of cause but unfortunately I'm not familiar with the Qt stack at all.
Btw the Colour Picker widget has the same issue. 1. Added to desktop: Works normally 2. Run 'QT_AUTO_SCREEN_SCALE_FACTOR=0 QT_SCALE_FACTOR=0.5 plasmawindowed org.kde.plasma.colorpicker': Works normally 3. Launch Colour Picker from KRunner or run 'plasmawindowed org.kde.plasma.colorpicker': Same problem as kcolorchooser reported here
Thanks for the reports and investigations. As it has been 10 months since the report on this can any of the affected please test and confirm if this issue is still occurring or if this bug report can be marked as resolved? I've set the bug status to "needsinfo" pending your response, please change back to "reported" or "resolved" when you respond, thanks.
KColorChooser Version 20.08.3 still occurring
can also confirm on Arch. btw apart from the env vars I mentioned above, QT_SCREEN_SCALE_FACTORS='' can also be used as a workaround.
Thanks for the updates. I'm setting this as confirmed as it affects multiple users .
AFAIU the problem is that QColorDialog always selects colors from the “primary screen”: https://code.woboq.org/qt5/qtbase/src/widgets/dialogs/qcolordialog.cpp.html#1574