The --designer launcher switch doesn’t work with Qt5 builds. It seems that it’s because the variable checked at this line is empty:
It would be great if this variable was set for Qt5 automatically. Any ideas how to make that happen?
Thanks to a PR of @adamrankin and inputs from @msmolens and @ihnorton , this is now fixed by 26856 and 26859
Commit r27608 fixes the lookup of the designer executable ensuring the one associated with the Qt5 version being is used is found.