Provide Horizontal Scroll Lock (for touchpad users)
Proposal: A 'horizontal scroll lock' button on the toolbar, which only allows scrolling up and down of the page when turned on. Reason: Quite often we need to zoom out the page to focus on the text(i.e. without the white margins), and it's not easy when using a multi-touch touchpad to scroll up/down (it goes left/right sometimes).
Edited by Andre Klapper