Feature request: move tab to the end of the tab list by dropping in empty space below tabs

[NikolausDemmel]

First of all, thank you very much for this nice plugin!

I have a kind request for an improvement, that you might want to consider some time:

I have the tab list on the left. I often want to drag one of the tabs to the bottom of the tab list. With Tree Style Tabs I could drop it into any of the unused space at the bottom of the tab list. With this plugin I need to drop it precisely in a small area below the bottom-most tab. It would be nice if dropping it anywhere in the hab area below the other tabs would insert it at the end (and at the first level).