Unexpected resize of ALL tabs on maximize following minimize. Not sure when this started happening. Maybe a week or so now.
Maximize after minimize to preserve query tab size
Just tried to reproduce that here, with a fourth query tab having 19 visible lines, after minimize/maximize still 19. Increasing to 39 lines does the same. Please post a screen of the sizes, so I can dig into that.
Is this what you need?

The dragging to make it bigger is the beginning of the loop, btw.
After some more investigation, here's the steps I found in order to get this to _stop_ happening:
I hope this is clear enough to help reproduce and possibly find a cause.
I have the same problem, it's super annoying.
This is still an issue, My heidisql resizes all my query tabs to "2 lines height" when I minimize and maximize every time.
Any progress on fixing this problem?