I have an app which pops up a form which is set to fsStayOnTop. If i use 'form.showmodal' then it will stay on top but 'form.show' does not it can disappear behind the main form. I have also found this behaviour using ShowMessage() and MessageBox they will end up behind the form and as its waiting for input will make it seem like the app has frozen. I tried this under X11 and works as expected.
Fedora 38, Qt 5.15.10, Lazarus 2.2.6 FPC 3.2.2
x86_64-linux-qt5