In SW2015, is it possible to customize the buttons in the "FeatureManager Tree" pop-up that comes up when you click a part in the feature tree?  There's a couple options that I rarely use that I'd like to move to a different position on the pop-up, or remove entirely. 

The picture hows the pop-up that I'm asking about.  If I right-click on it and select "customize", all the buttons are grayed out and I can't change them.  I can add buttons, but that's not what I want to do.