(Sorry for the late reply, for some reason I hadn't been notified)

>it's just that I'm hindered a bit by how to popup-on-hover doesn't disappear when we leave the thumbnail beneath
If you set "Popup position" -> "Beside Cursor" (as you wrote), and "Close when leaving thumbnail" (which should be the default), it should work, at least it does for me on Reddit... would you mind opening a github issue (link is on the addon page) for which site you're using that doesn't work (and maybe your settings as well, if you click "Export" at the top)? I'd like to fix this if possible :)

EDIT: I think I understand what you meant now. Previously, the behavior was to close the popup if the cursor was out of both the popup, and the thumbnail. In 0.12.5, you can now customize this to be only the thumbnail if you prefer (through "Close when leaving" -> Thumbnail)

>The Options page could be visually improved imo
I completely agree, this is one of my next priorities. Even I get lost in them, so that's definitely not a good sign haha. Thanks for the suggestions on how to do it, I'll keep them in mind! (tracked here: https://github.com/qsniyg/maxurl/issues/91)

EDIT: As of 0.12.16, I've implemented the frames feature you mentioned, and it also supports splitting categories into tabs. Thanks for the idea!

>And respecting the "dark themes" of firefox too would be awesome
Good idea! I've tracked it here: https://github.com/qsniyg/maxurl/issues/189.

EDIT: It's in 0.12.3 now, if you set "Dark mode" manually in preferences. Currently for whatever reason, detecting dark mode doesn't work on my system so I can't yet add support for automatic detection.

>oh, also an entry in the context menu for blacklisting an image
I've tracked it here: https://github.com/qsniyg/maxurl/issues/127, it might take a bit longer to implement though, as a new UI would have to be made for it. But I agree, it's quite important.

>could you improve instagram support for posts that have more than 1 image/media in it
Yes, that's also something I've been thinking of working on soon. I'll try to do it in the next release if possible :) (tracked here: https://github.com/qsniyg/maxurl/issues/50).

EDIT: It's in 0.12.3, if you enable "Use albums for Instagram post thumbnails".

>Thank you for making it, improving it so much over time, and for making it open source
You're very welcome, and thanks for taking the time to write that! :)