After a lot of scrolling, lines of text start to dance up and down by a single pixel.

[jcdyer]

When scrolling through a long page (http://en.wikipedia.org/wiki/Washington_Irving), lines of text start shifting up and down by one pixel. Not all at once, each line shifts independently of the others.

It may be triggered by moving the window. It also seems to peg the CPU for several (15-20) seconds.

Seen on a servo built from master checked out today.

Output:

work@waller:~/src/servo$ ./mach -lwashirv.log --verbose run http://en.wikipedia.org/wiki/Washington_Irving    
Bad header encountered. TODO: handle this better.
Bad header encountered. TODO: handle this better.
Bad header encountered. TODO: handle this better.
Bad header encountered. TODO: handle this better.
Bad header encountered. TODO: handle this better.
Bad header encountered. TODO: handle this better.
Bad header encountered. TODO: handle this better.
Bad header encountered. TODO: handle this better.
Bad header encountered. TODO: handle this better.
Bad header encountered. TODO: handle this better.
Bad header encountered. TODO: handle this better.
Bad header encountered. TODO: handle this better.
Bad header encountered. TODO: handle this better.
Bad header encountered. TODO: handle this better.
Bad header encountered. TODO: handle this better.
Bad header encountered. TODO: handle this better.
Bad header encountered. TODO: handle this better.
Bad header encountered. TODO: handle this better.
Bad header encountered. TODO: handle this better.
ERROR:js::rust: Error at http://bits.wikimedia.org/en.wikipedia.org/load.php?debug=false&lang=en&modules=startup&only=scripts&skin=vector&*:1: TypeError: ua is undefined

evaluate_script failed
Bad header encountered. TODO: handle this better.

In spite of (trying to) enable verbose logging as specified in mach run --help, the logfile is created, but empty.

[jcdyer]

Seen on a kde desktop under Debian Jessie with all packages updated.

[mbrubeck]

Can't reproduce this in more recent builds. Maybe fixed by #7161 and related changes.