Split Scroll Sync by Andreas

Firefox can show two tabs side by side in Split View. Split Scroll Sync makes both sides scroll together – perfect for comparing contract drafts, translations, documentation, product pages or two versions of the same site.

Features
• Detects Split View tabs automatically
• On/off switch right in the page: appears in the top-right corner when you move the mouse
• Also toggled via the toolbar icon or the shortcut Alt+Shift+Y
• Two modes (right-click the icon):
– Proportional: both pages stay at the same relative position, even if they differ in length
– Pixel: both pages scroll by the same distance, keeping any existing offset
• Works with web apps that scroll an inner container instead of the whole page
• Without Split View: select two tabs with Ctrl/Cmd+click and click the icon to pair them manually

Privacy
This add-on does not collect, store or transmit any data. Scroll positions are only exchanged between the two paired tabs inside your browser.