The button is meaningless, it is on any window. We really need an addon that, instead of closing the window, firefox throws it down (minimizes), so that the "close" button works just like "minimize". Old addons (Minimize to tray and "minimize when close, close tab (s) on Esc (Delete)") do not work! Please make such an addon.
Exactly what I was looking for. I use it on Xubuntu (with XFCE). I configured my system so that there is no titlebar in maximized windows. I put the Close button into the tab bar. So I can still close the window with ease.
Works great! A must for those of us who hide the titlebar or customize nav / bookmark / tab bar order, allowing us to put the close button wherever we want! The authors' other button addons work great as well!
Feature Request: allow us to pick the button color so we can match our theme colors! =)
Simple, but useful. Means I can remove window manager's titlebar to save space and just use this extension to click and close Firefox. Any chance of having an option to place it at the left-hand side instead? (This is where I normally place my window manager controls.)