@Angus I stand fully corrected. QFileDialog that the commit I pointed at added is the correct approach, but MR 17 you’ve pointed it added the FileMode in the wrong place - when it was added after setOptions(), it reset the options and caused QFileDialog to not use the directory only selector.
Possibly, or it worked at the time and Qt had a behavior change 
.
Anyway, I fixed the MR to fix the problem.