Running Firefox version 159.0 on Fedora Linux Workstation 44, both the RPM and Flatpak versions at least have very old looking right click context menus (see image attached) which looks very out of place with the rest of modern Firefox and other Gnome apps.
I noticed that everywhere I right click in Firefox (eg on the tabs, toolbar or in the webpage itself) it is formatted in what feels like an old school theme even on a fresh install of Fedora on Firefox 159 with no addons etc installed.
I would expect it to look more like when you click on Firefox's top right Application Menu, or when you click on the Downloads button or Extensions button etc. Notice how all those pops ups are presented in a consistent rounder more modern padded style.
I launched the Fedora Workstation live ISO to compare Firefox 146.0 to 159.0 and I think the issue is much more noticeable now that the rest of the Firefox 159.0 interface matches more closely to the default Gnome desktop theme now and so now the right click context menu looks really out of place (where as in version 146 it was the same right click context menus but the rest of the UI was almost similarly formatted like them).
Basically hoping for a better looking right click context menu to more closely match the rest of the nice theme the Firefox dev team has created. Likely needs slightly more rounded corners, a smig more padding, the horizontal lines tweaked etc.