I normally run a three monitor setup with a 4K monitor in the middle. Sadly today the 4K monitor had to make a trip back to ist maker and I replaced it with an HD monitor. So the screen height has gone from 2160 down to 1080 pixels. Now when I start Heidi it is half off the top of monitors 1 & 2 and because the title bar is missing, I can't drag it back down.
I read a few posts where you said Heidi does a check that it is on screen, but it doesn't seem to be working.
It would be great to find a little utility that lets you reposition any currently displayed window.