=================== by Aleksandr Seleznev (Developer) on October 24, 2017 · permalink
Web Extension API doesn't provide any way to hide titlebar. You can try to use external process via Native Messaging API, but it isn't good solution (a very bad hack actually) and will have complicated installation instruction. I have no plan to make it.
Mozilla Firefox will have native support for CSD soon (not sure that it will be shipped in Fx 57). You can track progress in https://bugzilla.mozilla.org/show_bug.cgi?id=1283299 and help with testing for example. ===================
Sorry for starting another post but there isn't a reply option so i just wanted to thank you for taking the time to explain that the new Firefox CSD will resolve this issue in later releases , It looks awesome. :)
Here is a Link of how it looks if anyone is interested.
I really appreciated this addon for the vertical space savings that it gave. Unfortunately it does not work anymore. For anyone looking for an alternative in Gnome the Pixel Saver gnome addon (https://extensions.gnome.org/extension/723/pixel-saver/) works great!
This is a GREAT extension... But with Major issues. Firefox set to maximized in GNOME is far from maximized. A HUGE titlebar Dominates the top and Wastes an excessive amount of space without this extension. The problem, Well, other than this being an issue to begin with, is that the development of this Great extension has been discontinued and the new changes in Firefox make it harder to use as of Now, however, it will stop working all together relatively soon. This is such a negative for me that it will force me to change either to a different browser or perhaps to a different Desktop Environment. It sure would be nice if this could be fixed somehow without making such a change.
I'm using this on Fedora 25, Gnome 3, and Firefox Developer Edition on the Aurora channel; so I'm running the newest of just about everything. This add-on works great, and does exactly what it's supposed to do. It also has an option to hide the title "always" (Rather than just when it is maximized) which is super great for me, as I always have my screen split in half with text editor and terminal on one half, and Firefox on the other. I hope someone takes this project on to keep it running (or merges it into core), as I can't stand the huge title bar!