@Alexandru Nedelcu -- Any way to restore the window control buttons (e.g., min, max, close)?

TST is a great addon, but the need to continually write your own CSS code to make it behave within reasonable expectations is frustrating. Moreso, the changing css code makes this work-around unreliable; see above. The latest change to FF has rendered the previous solutions obsolete: eliminating the duplicate horizontal tabs using the previous method also eliminates the window controls.