When I click on the Bookmark tab and move my cursor down the list, I used to be able to hover over a bookmark and a second later I would get a small "pop-up" that would have the complete URL in it. Lately, if I hover over a bookmark, I still get the small window, but it is blank. I've had this issue for several months, thinking that an update would fix the problem, but it hasn't. I have the current version of Firefox. The image attached shows a screenshot of the issue. I am hovered on "Craigslist". You can see the blank "pop-up" as indicated by the arrow. This is on a desktop version, by the way.