Just wondering if anyone else is experiencing this. There is a very short delay when exiting Firefox by clicking the upper right "x". I do not notice this with any other application, and I have not seen this behavior on other distros that I have tested or on Windows. There is no delay on closing open tabs either. Not a big deal.....just curious.

Yes, this is something of a longstanding problem. Though testing it again just now it seems like the Firefox 68 update might've fixed it. Currently in the Unstable repository and will arrive in Stable with the next sync.

Did you disable some language packs in the settings?
The problem is that Firefox comes with all langpacks enabled by default, and thus it loads every translation on launch and unloads everything on close, and that can cause slight delay due to large amount of data in these packs. Try disabling everything except your locale, this can help.

    aleksvor
    That did the trick.
    I'm unable to edit the original post heading. How can I mark this as "solved"?