Goodmorning, I've noticed this issue only in vanilla firefox (not the forks of it) and only in .rpm builds so the .exe, .deb and tar.gz are free. My firefox is generally fluent without any problem but when i go into the sidebar menu and select the bookmarks, history and other categories witch have another animation transition this is completly laggy and not fluent as it should be, and when i tested this issue on (for example librewolf a fork of firefox in the same versions) this issue wont happen so only vanilla firefox may be affected. I'm currently on fedora 41 GNOME with wayland always uptodate and firefox 134.0.2 but this issue happened also on open suse and other rpm distro. I had this problem since a lot but i found that firefox-esr haven't this issue (tested on opensuse leap). Hope all this info will be helpfull and thanks for your help. (ps: english is not my first language)