OS is Win7-x64, graphics Intel HD Graphics on Haswell pentium G3220 with latest available driver. Since version 89.0 or 90.0 (not sure which) following webpage rendering issues appeared on my machine: - page loads ok, but when I scroll up/down with pageup/pagedown keys then some keystrokes are not followed by redraw, or redraw is partially blank (horizontally split - see attached screenshot). Subsequent keystrokes either have the same problem or are rendered correctly. - scrolling is only problematic with pageup/pagedown keys. Alternative methods (up/down keys, mousewheel, holding and dragging scrollbar or clicking above or beneath it) work ok. - I'm sure that version 89.0 or 88.0 didn't have this problem. Since then I haven't changed any about:config settings or updated graphics driver. Compositing was then and now set at WebRender (not WebRender (Software)). - I tried disabling hardware acceleration on version 92.0, but it hasn't solved issue, so I reverted this back. Troubleshooting info is attached. Thanks in advance for your help.