Rated 4 out of 5 stars

Pros: Does what it says on the tin.
Cons: It seems to slow down navigation through the bookmarks.

This review is for a previous version of the add-on (2.3.0.1-signed). 

1. EditBookMarkPlus does not interrupt the bookmarks navigation in any way, It waits quietly and only works at the moment when the bookmarks popup is displayed and simply resizes it once. This might have been caused by some other extension. Disable all other bookmarks related extension and see if this improves the situation.

2. This can be disabled by unchecking the "Only Cancel/Done or Remove button close the popup" checkbox in extensions options dialog.