Linux, X11.
Extracted from #949 (comment)

I played with holding Ctrl +/- and found a silly issue, posting just in case you can immediately think of a simple fix, otherwise I guess it's not worth looking into:

• Hold Ctrl +. The value reaches its maximum value (274 in my case) and stays there, pressing Ctrl + further has no effect. Pressing Ctrl - once reduces font size to 272.
• Now hold Ctrl -. The value reaches its minimum value (2 in my case), but further presses of Ctrl - change the value to 2, again and again. If I press Ctrl - 10 times after I already reached the minimal value of 2, then pressing Ctrl + once will have no effect - the font size will stay at 2. I have to press Ctrl + 10 times to compensate for my earlier actions, before further presses of Ctrl + begin to actually increase the font.