Just as simple as the title says — an option to only show the bookmarks bar when the toolbar is hovered. Maybe show the default bookmark bar show/hide animation to make it more logical and eye-pleasing.
Came here looking for this. I use Firefox for home and work, and login using the same Firefox account. For work, I'll often give demos using the browser, and my personal bookmarks show up until I hide them. It would be really cool to have those not show, but instead be mouseover or toggleable with a hotkey.
Bookmarks are a paramount functionally for everybody. Each person uses them differently (quick access, permanent/transient storage, etc.), but we all need 1) privacy (ex. sharing screen in videoconferences) and/or 2) just more screen space (ex. laptops). An option to activate/deactivate the autohide of the bookmarks toolbar and bookmarks sidebar (one for each) would be very interesting.
Additionally, in the bookmark toolbar an explicit option to center the icons would be very welcome, also.
This is a nice idea, and similar to other posters above, this would be super useful for demos, videos and screenshots. Currently I use the built-in keyboard shortcut to show/hide the bookmark bar (Mac; Shift+Command+B), but I'm all about automation.
Often the user doesn't have his left (or right) hand on the keyboard when just using the mouse to browse.
So without an auto-hide feature, which is clearly the best option, reaching for the keyboard with the other hand is just inefficient let alone annoying.
Being able to customize the toolbar/titlebar with a button for toggling the bookmark toolbar would be a nice option regardless.
I came here hoping to find a way to show the Bookmark Toolbar on one window but on another. I've been terribly dissatisfied with the 2 options currently available: always show or only on new tab. Seriously?
I certainly am not comfortable messing around with userChrome.css although I've done it a time or two. I'd just rather not have to do that. (Thanks anyway, Agentvirtuel )
This idea here (hover to show) is fabulous! Come on FF! Let's make this happen!
Maybe it could be similar to the "Show desktop bar" on Windows' systray (bottom right corner of the screen). A slim bar/button that, when clicked, shows the bookmarks toolbar. Just a suggestion, as the auto-hide function seems to be too much to ask for.