The Qt5 version(s) have a problem when using them with the i3 Window Manager (Debian GNU/Linux 11).
When starting a new C/C++ Project after answering the question to create a new directory for the project, the Project type pop-up window is not always shown and SlickEdit becomes unresponsive.
I experienced this the first time I tried to create a new project, but not the second time (after killing the slickedit process and restarting), I tried switching the main window in Floating mode and move it offscreen, sometimes this helps bring the window underneath into view, but not in this case.
This only happens with the Qt5 versions of SlickEdit, the Qt4 releases don't have this problem.