I have a Tree Control like the scene tree in the editor. Mouse support works as you'd expect (click to select, and shift+click to multi-select). However, arrow key support is a bit wonky.
- Moving up and down only moves a special cursor and doesn't change what is selected.
- Shift+up/down should add to selection, but it just moves the cursor.
Note: I have the Tree's Select Mode set to Multi which is the only mode that uses the cursor.