(optional): Disable smooth scrolling (Firefox & Windows preferences too).

1. Open the URL in your Firefox: `about:config`.
2. Set new values in config:
`mousewheel.system_scroll_override_on_root_content.enabled` = **true** (by default is ***true***)
`mousewheel.system_scroll_override_on_root_content.horizontal.factor` = **196**
`mousewheel.system_scroll_override_on_root_content.vertical.factor` = **196**