Most problems I found when installing/using the GNOME edition were related to Qt:
In HiDPI screens at 2x or more scaling factor, all Qt apps (including those that are Manjaro-specific: Calamares installer, Settings Manager, etc) look tiny and distorted. This is because Qt auto-scaling (
QT_AUTO_SCREEN_SCALE_FACTOR=1) is not set in the environment. Most Qt apps work just fine out-of-the-box with auto-scaling and those few that don't require some kind of taylored manual scaling anyway (using
QT_SCALE_FACTORor similar) and, in any case, for those marginal cases, it's better a little-bigger/smaller-than-ideal app than a tiny one. Fedora, for one, is a distribution that cares about Qt integration (after all, they develop adwaita-qt theme and QGnomePlatform) and they set
QT_AUTO_SCREEN_SCALE_FACTOR=1by default. Just try installing/running Manjaro on a 4K screen and I'm rather sure you will agree that something has to be done.
- A font that is of different family and size than the one set for GNOME.
- Dark-theme icons that are too light to be seen (very low contrast) in the configured kvantum theme (which is light, matching the GNOME theme). This is specially manifest in the Qt file dialog: most icons are barely visible.
- To use Qt system dialogs (the other option is GTK2) which don't neatly integrates with the rest of the system.
Honestly, I see no point in using qt5ct to set features that diverge so much from the ones in the host environment. Besides qt5ct doesn't seem to support system (GTK3) dialogs. These days by just leaving
QT_QPA_PLATFORMTHEMEalone you get pretty good integration: fonts, dialogs, icons are mostly ok. You can then override style:
QT_STYLE_OVERRIDE=kvantum. This way you have one less dependency and all three points above fixed without the need to coordinate GTK and Qt settings. Another option is to use QGnomePlatorm, but I see little benefit in doing that (OTOH, it's a game changer in Wayland, since it renders decorations following the GNOME theme).
The provided kvantum theme suffers (as too many kvantum themes) from https://github.com/tsujan/Kvantum/issues/399. This doesn't match the GNOME theme: menubar and toolbars take the color (dark) from the headerbar or titlebar. Worse: only one toolbar is dark, which makes for a doubly inconsistent experience. Worse: icons that look good in a light background may look awful or show accessibility problems against a dark background. Fortunately, Kvantum author has shown how to fix that by a simple modification of the theme: https://github.com/tsujan/Kvantum/issues/399#issuecomment-502512707. I find it sad that the author doesn't agree with changing this upstream as IMO current behavior is problematic in most cases but, anyway, he provides a simple way out.
Note: moderator - this is not a regular issue - moved to rants