SUMMARY Settings to open file/folder with one/double click doesn't work for Qt6 applications built with not system's Qt6 STEPS TO REPRODUCE 1. Build Qt6 app, or even use QtIFW installer built with not system's Qt 2. Try to use open file/folder dialog 3. OBSERVED RESULT In this dialog system's settings for one/double click doesn't work, and files/folders opens in one click even if in system's settings set using double click. EXPECTED RESULT System's settings should be regarded in any Qt6 app. SOFTWARE/OS VERSIONS Windows: macOS: Linux/KDE Plasma: KDE neon 6 (available in About System) KDE Plasma Version: 6.0.0 KDE Frameworks Version: 6.0.0 Qt Version: 6.6.2 ADDITIONAL INFORMATION
It'll work in any Qt app using the plasma-integration QPT, which is where this gets set. If your apps aren't respecting this, it's time to look into integration issues with your setup.
I asked at Qt here: https://bugreports.qt.io/browse/QTBUG-122940 They said to ask you. Whom should I listen, and what should I do?
It's not a problem with KDE and it's not a problem with Qt: it's a problem with the applications. They are not using the system Qt so the settings of the system Qt (provided by the Plasma integration plugin) don't affect them. There is nothing KDE or Qt can do about it.
Qt has a platformtheme implementation for Plasma that gets used when plasma-integration is not available. That reads the double-click setting, but doesn't handle the default value correctly. https://codereview.qt-project.org/c/qt/qtbase/+/544763 fixes that