I had this app rattling around for the longest time without really using it, but now I've re-discovered it.
And for some websites it's just SO nice to have them as normal little windows instead of tabs.
My music player, and various chat websites are just much cleaner and easier to deal with as stand-alone windows.
I originally installed the Slack "app" just so I could have it in its own window, but then the app broke and I've used slack.com as a popout window with this extension ever since. It's the small things :-D

Convert a tab into a popup window works well. but when I merge popup, the firefox windows missed. I use "Sizer" software to get windows current position, it is outside screen. (my monitor resolution is 2560x1440, but firefox windows position at left:2757 top:83)

It works! Firefox 121.0.1, Arch Linux, i3 WM (X11)

This extension has remember window size, which is awesome! great Work!

✨ 🏆 💎 🥇 ✨ AMAZING!! ...One of my DEFAULT MUST HAVE EXTENSION!

This extension is extremely underrated IMO.
Especially since Firefox discontinued the beta for the very long awaited PWA & in-browser Web App functionality.
So this is pretty much the closes us Firefox users are going to get, which makes this tool a very special HIDDEN GEM!

🙏 🙏 🙏 🙏 🙏
Thank you so much to the developer who's always continued to make sure it stays stable and efficient.

I use a trio of extensions for pop-ups.

Focus Popup https://addons.mozilla.org/addon/focus-popup/ has a keyboard shortcut (Control-Shift-7) and can duplicate a tab into a pop-up (without history) whilst leaving the original (with history).

PopUp https://addons.mozilla.org/addon/popup/ preserves tab history when popping up, and allows me to choose the window in which a pop-up should be restored, but has no keyboard shortcut – https://github.com/aqt/webext-popup/issues/37

Popup Tab https://addons.mozilla.org/addon/popup-tab/ preserves tab history when popping up, and has a keyboard shortcut (Control-Shift-8) that works with Waterfox 56.2.7.1.

Love that you can use this to turn any tab into no-extra-crap fullscreen mode with F11

It's excelente. It does what it describes. I recommend it

Thats just handy. :)

Works really well! Page doesn't get reloaded when switching display mode, and converts both ways between tab view and popup view. Much better than similar extension for Chrome.

I hope this add-on has added the ability to automatically turn pop-up into tab.

Currently this plugin is only able to merge back popups that are popup by this plugin.

This is exactly what I was looking for, thanks much.

but add an option - Alway on Top

Removes the tabs, URL bar, and all other UI elements except the scrollbar and menu bar. Perfect for focusing on the content itself.