Comment 1 for bug 281911

Previously it worked better: Press and release got in to the selection mode. Then it required a selection or the escape key to exit the selection mode.

Now as stated above it is just unusable since you have to hold the key down during the selection. Release of the key will cause the selection mode to abort.

The best solution would be to work as the old behaviour with the slight modification to accept the same keypress to exit the selection mode as you use to enter it.

If you have f12 to get in to selection mode I see this workflow:
f12 (press and release) gets you to the selection mode.
Select a window or f12 (press and release) exits the selection mode. I can see that escape might be good to accept also.

I think this bug is quite urgent since it makes the scale plugin totally useless.