Linux, X11, on a laptop with touchpad.

To reproduce, build something to produce a bit of text in the compile output pane. Then press the control key to enable zoom mode and flick the touchpad so that the text becomes very tiny. 

Qt Creator will lock up. It seems like the limits of what the smallest scale factor can be is not checked properly. Sometimes it catches it and stops, but sometimes not.

My guess would be that the limit is checked with == but the fast flicking changes the scroll multiplier in bigger steps, skipping that particular value and it ends up calculating some infinite number or so.