I've noticed that some times the ROI rect box lags quite a bit. Also, it seems when selecting the top handle to resize, the boundary of the rectangle moves, but the handle stays in the same place (see image). Also, when in 1-button mouse mode, the zoom region does not follow the mouse when it the mouse mouse below the initial drag point.
Tangentially: is it possible to "go back" after a 1-button region selection event?