To try the thousands of add-ons available here, download Mozilla Firefox, a fast, free way to surf the Web!
CloseWelcome to Firefox Add-ons.
Choose from thousands of extra features and styles to make Firefox your own.
CloseReview for CompactHeader by kman0
Rated 3 out of 5 stars
If you use the Customize Header functionality to remove all the buttons (Reply, Archive, Delete, etc) - and then collapse the Header - there's a strange different-colored "box" of space where the buttons would go.
With the Header expanded normally, everything is fine. No weird box. But if you collapse the Header (and don't have any of the buttons on there) - then you see it.
To create your own collections, you must have a Mozilla Add-ons account.