+ Have system settings that prefer English (US), German as second choice.
+ Open Assistant/Designer/...
+ The used UI language is german instead of english
This is a regression: In Qt 5.15.1 all GUI applications are showing up in english.
|For Gerrit Dashboard: QTBUG-87858|
|320696,3||Fix accidental shadowing in QLocale::uiLanguages()||dev||qt/qtbase||Status: MERGED||+2||0|