Is this with using a real mouse or a touch pad on a tablet? You can try to disable hardware acceleration in Firefox. *Tools > Options > Advanced > General > Browsing: "Use hardware acceleration when available" You need to close and restart Firefox after toggling this setting. *https://support.mozilla.org/kb/Troubleshooting+extensions+and+themes *https://support.mozilla.org/kb/upgrade-graphics-drivers-use-hardware-acceleration You can check for issues caused by plugins and set all plugins to "Ask to Activate" on the "Firefox/Tools > Add-ons > Plugins" page (plugins are not affected by Firefox Safe Mode) *https://support.mozilla.org/kb/Troubleshooting+plugins