Must have for Firefox. In my case, it handles 300+ tabs without a problem. I really don't get it, why functionality like this is not build in FF.

Great extension. helps me organize tabs more easily

Thank you very much for this extension, but I want to tell about a little inconvenience that is happening to me while using the Tree.
When I close the tab that is not the last in the tree, all the tabs below are going up to fill empty space of the closed tab. It results in creating a gap at the bottom of the tree, which persists until the tree loses the focus of the mouse.
The most irritating in this behavior is the fact that I cannot close multiple tabs from bottom to top (as I wish) without being forced to move the mouse up or away of the tree.
This problem appeared several months ago, there were no such a problem earlier, I could close buttons in convenient way from bottom to top, and for now I just keep searching for the option to revert the classic behavior, but there is no any (or maybe I don't see?).
Please help me to fix this issue, or please add such an option, it maybe should be something simple, like "ignore the mouse focus while closing the tabs", or "do not allow the gap at the bottom of the tree".
I would be really grateful if you do so.

Tree Style Tab de Piro (piro_or)

I often open multi FF windows. Every start up FF it will display Tree sidebars from all those windows. Then I have to undisplay Tree sidebars on some windows because those windows are just targeted to have very little opened tabs. Only main window for Tree sidebar. Does it have an option to save on/off thing?