Hello everyone

I had a Firefox extension and i want the button add to toolbar
automatically, and i really did that.but i had another problem to
solve, i add it to toolbar by using insertItem, this method is called
like navbar.insertItem ('toolbar-button', null, null, false); and this
really work. but the button add at the left side of the address bar,if
i want to add it to the right of the address bar, such like some user
customize the button it self, how can i do that?