VBO Back2Root
This script do a quickly get user back to root level( level 0) of the model and select none. It will save a lot of clicks or Esc key pressing when you are working in deep levels.
VBO Back2Root

This plugin brings you back to model's root level from any level(s) of Group/Component edit and also clear the selection too. This feature has the same effect with a click on "model" in Outliner Dialog, but you can give it a shortcut key for more comfort in modeling.