I have ~50 variables in my tree, which I like to keep organized. Every time relocating or adding a variable turns into a lot of clicking. My suggestion is very simple:
- new variables always appear on top
- left click moves 1 position
- shift+left click(or just right click) moves 10 positions
- new variables always appear on top
- left click moves 1 position
- shift+left click(or just right click) moves 10 positions