You should provide links and examples of the issue for those of us that don't use Social Media. Post a screenshot of what it looks like in Firefox and another browser that works for you. Did you try with Firefox in Safe Mode? https://support.mozilla.org/en-US/kb/diagnose-firefox-issues-using-troubleshoot-mode#w_how-to-start-firefox-in-4troubleshoot-modesf5safe-modesf

What sort of input devices are connected? Do you have any kind of touch screen or pen tablet device enabled?

Go to about:config in the address bar and create ui.primaryPointerCapabilities (Number) with value 6 (fine pointer with hover capability).

WARNING from the moderator team: Changing Firefox preferences from the about:config page can sometimes break Firefox or cause strange behavior. You should only do this if you know what you're doing. Please read Firefox Advanced Customization and Configuration Options to learn more.