Scroll Anywhere enables you to drag scrollbar with your middle (or right / left) mouse button without actually touching a scrollbar. Just hold the middle mouse button and move up-down or left-right. You can also change the behavior to simple "grab and drag" style. Available also for your Thunderbird 78 email client! Short preview video here (0:12) Warning: very addictive! :) Features:

Momentum allows you to throw page to scroll it faster (just like on your phone)
Middle / Right / Left mouse buttons are supported, see the Options page
Customize scrollbars - make them thinner, change color or hide
Auto-disable on specified domains / sub-domains
Grab and drag scroll like on your phone
Multiplier to speed-up or slow down
On key down enable / disable
Custom scrolling cursor

Contribution:

I've spend more than 1,000 hours developing this add-on. Please consider supporting my work by:

Buy me a coffee

PayPal donation

Become my Liberapay supporter!

Patreon

Thank you! :) Your donation will help me keep this add-on working in future versions of Firefox!

Social media: Facebook / Twitter Known issues:

does not work HERE on https://addons.mozilla.org/ (blocked by Firefox)
does not work on browser specific pages like "about:addons" (blocked by Firefox)
does not work in "PDF view" - broken by Firefox 60
does not work in "reader view" (blocked by Firefox), vote for bug
does not work on other extensions pages like options page of some addon (blocked by Firefox)
may not work in nested IFRAME html elements (somehow Firefox won't inject it there)

Be aware:

left mouse button support is experimental feature - please report any issues to my support e-mail.
Linux users may want to enable "Don't block default button action" option in Options/Advanced - to enable 'Paste' with middle button again.
in some Linux versions you may need to disable "middlemouse.contentLoadURL" in "about:config" to avoid navigating to URL from clipboard when pressing middle mouse button

Recently added features:

The list of changes in last versions is available here

Tags: anywhere, button, cursor, drag, grab, grab drag, grab and drag, infinite, left, middle, momentum, mouse, move, page, right, scroll, scroll page, scrollbar, scrolling, throw