In the Tag Customization window, you can use Ctrl+Up and Ctrl+Down to edit the previous and next tag or state.
You can use Ctrl+Shift+Up and Ctrl+Shift+Down to move the current tag or state.
You also can press Suppr while the tag tree is selected to delete the current state or tag.
Finally, you can press F2 in the tag tree to move the focus to the tag or state name field.