Hello. Apologies, the title is very ambiguous as I was unable to come up with a more specific one with an appropriate length (or rather, lack thereof). This issue has been bugging me for a while now and I just realised when exactly it arises. When changing the proportions of selected nodes in the proportions palette (the one stuck to the glyphs info box) using arrow keys, while holding down space to keep the preview active, after pressing an arrow key up or down once to increase or decrease the value, the proportions change once, but then the text box for entering the value is immediately exited. So, if you press the arrow key again, you end up moving the nodes. Very annoying, for instance if you use shift to increment in steps of 10. units and suddenly move all your selected nodes by 10, 20 or more units.
So, as this was quite a complicated explanation, to reproduce:
- select some nodes
- In the proportions palette, click into the x or y distance box
- hold down space to keep preview active
- while holding space, use the arrow keys to increase or decrease the value in the text box
Result: the text box is exited and you would now move the nodes with your arrow keys.
I am unable to say whether this is still an issue in Glyphs 3 (as I didn’t test this during beta and am still angry with myself that I missed the grace period by one week), but it persists in Glyphs 2. Not the most urgent of issues, I am aware, but still something that really annoys me regularly 
Thank you!