Rated 4 out of 5 stars

It is great, but does not work well with Nostalgy++ extension. I cannot write into the floating panel (nothing happens), but Nostalgy grabs the keystrokes. If I change it to "Popup window", it works well, but this popup always pops up in the center of the screen and positioning does not work.

This review is for a previous version of the add-on (0.10.4). 

You can bump Nostalgy++ author to apply a fix:
https://github.com/opto/nostalgy-xpi/issues/128#issuecomment-1100380599