Created attachment 103817 [details] Tray icons too small (iconSize == 1) On hidpi monitors the standard tray icon size easily becomes too small to suit the size of the panel. See attached image. A workaround is to edit /usr/share/plasma/plasmoids/org.kde.plasma.private.systemtray/contents/config/main.xml and change iconSize from the default 1 to (generally) 2, but then it's still not scaling automatically and the change doesn't persist over package upgrades. It cannot be changed via systemsettings. An additional workaround suggested by Fuchs over IRC is to keep a local copy in ~/.local/share/plasma/plasmoids, with the drawback of freezing it, not enjoying any further improvements or bugfixes to the plasmoid. This is on a machine running Arch amd64, with Plasma 5.9 from the official repositories.
Created attachment 103818 [details] Tray icons much better (iconSize == 2)
This bug looks related to bug 360333.
This isn't anything to do with high DPI, it's just a design decision. One that hopefully we will revisit. *** This bug has been marked as a duplicate of bug 360333 ***