I have stumbled on a rendering problem with Firefox-45-ESR and Firefox-52-ESR on Debian-8-stable (jessie) and Debian-7-LTS (wheezy). Firefox is unable to render long text files correctly. At least not with default settings. This happens on Debian stable and LTS precompiled versions of Firefox-45-ESR, and also self compiled versions on Firefox-45-ESR and Firefox-52-ESR, also with newer gcc versions. My test computer is running old-school sysV-init and fvwm window manager. The problem occours on both bare-metal hardware (intel graphics driver) and Qemu virtual machine (-vga std) so graphics driver does not appear the be the problem.
I also booted Ubuntu-16.04.2 live-DVD image. This problem does not occour on that live-DVD, so this appears to be Debian specific. Example long text file, 33+ megabytes: http://mirrordirector.raspbian.org/raspbian/dists/wheezy/main/binary-armhf/Packages Same rendering problem happens if that is loaded from local file:///tmp/Packages Demo screenshot, beginning of the page, this is OK: http://www.saunalahti.fi/~jariru8/misc/ff-render-1.png Demo screenshot, end of the page, this is rendered incorrectly: http://www.saunalahti.fi/~jariru8/misc/ff-render-2.png The beginning of the page is rendered correctly, but end of the page is not. To see the "mess" press the END key on the keyboard, or scroll the page to the end. Then maybe press cursor-UP and cursor-DOWN keys to scroll the page, more "mess" appears. On Firefox-45-ESR (and older versions) this bug can be worked around by setting these in about:config html5.offmainthread = false layers.offmainthreadcomposition.async-animations = false layers.offmainthreadcomposition.enabled = false The problem is that Firefox-52-ESR is soon the be the only security maintained version, and that version no longer respects those "offmainthread" workarounds. Any ideas how to work around this problem on Firefox-52-ESR? -- Jari Ruusu 4096R/8132F189 12D6 4C3A DCDA 0AA4 27BD ACDF F073 3C80 8132 F189
