How do you rate something that only partially works? Great idea, but difficult to work with.

When it worked for me, it was nice to have a Firefox browser window with no UI elements at all. Like Chrome apps.

But no matter how I try, the extension doesn't seem to work except with the --app parameter added, and I only got it to work once.

I really hope the developer gets to devote more time to this, Firefox really misses this.

Almost a 5 star extension, if it worked the way it ought to.

Expected: A hot-key, like CTRL+F11 to toggle hide/show of browser UI elements in the current tab.

Actual: 1. Disable extension; 2. Open a new window with the desired website. 3. Open Manage Extensions page; 4. Enable extension -- the first tab will now pop out into an undecorated window. 5. Disable extension.

I sooooo wish it worked properly, as I frequently want to reduce a tab to an absolutely minimal UI.

Just installed this, saw it didn't work at all, then tried the workaround mentioned by Firefox user 13997589. That didn't work the way I was expecting it to, and I had no idea to get out of the chromeless window. When I finally did, and finally got back to my prior tab group (via the Simple Tab Groups addon), all my history for each tab was gone (only the most recent page in each tab was preserved). I was looking for an equivalent of the Ctrl F11 feature in Vivaldi that easily TOGGLES the browser UI without going fullscreen. I'm using Firefox 85.0.2 on Manjaro Linux. I'm removing this addon for now.

This is a great workaround after the update mentioned in Bug 1664477. Thanks a lot!

=Edit=
By the way, despite that the extension is a bit buggy, I still gave 5 stars because it's currently the ONLY solution. This is the way I use the extension:

=How to prepare it=
1.- Install the extension.
2.- Press the extension button active it (as seen in the screenshots).
3.- DISABLE THE EXTENSION! The idea is that the on/off button of the screenshot must be on an active state (green) before disabling, so it resumes when it gets enabled.
=How to use it=
1.- When you want to get a clean window, open a new window and go to the page you want.
2.- In that new window, press Ctrl+Shift+A or manually go to the Addons manager.
3.- Enable the extension. This action will turn the first opened tab of the current window into a new clean window.

(this works for me with Firefox 84.0.2 under Manjaro Linux, but I don't see why it shouldn't work on Windows or MacOS)