Open bookmark and history folders in Library and Edit This Bookmark will automaticly close themself when opening another one.
You can set disable or enable with an option.
If Firefox gave you the following error message:
Firefox could not install the file at
because: Invalid file hash (possible download corruption)
This error message may be caused when the Firefox disiallow third party cookies.
To accept the third party cookies:
go to Tools -> Options -> Privacy -> tick 'Accept third party cookies'.
· Mozilla Firefox