App shows no window

Just downloaded it onto my secondard mac via the store, and what was working fine on my laptop, is a no go on my iMac. Simply no application window appears. Menu is there, but no matter what I do, I can’t see the app window. Reduced window from the menu gives a weird small squished icon in the dock. Bummed out.

Drooooog about Dupin Lite 2, v1.0.5