I’am having difficulty in getting gestures to work properly. I always succeed with the grab, which I use all the time. But often the gesture I use for scaling turns into rotation and vice a versa, even though to me it looks like I have drawn the correct gesture. Any pointers on what to do right would be useful, perhaps a picture of the correct gesture.

Draw a Z and let go just as you start the bottom stroke. (You really only need a V, works too).