I'm using a binary distribution of Mozilla 0.9.9 for Linux x86, on Redhat 7.2 with XFree86 4.2.0 RPMs from rawhide. With a completely default profile (I moved my normal .mozilla out of the way), if I load the test case (see URL) and make my window sufficiently narrow (under about 500 pixels, with the sidebar turned off, seems to do the trick), the content area is overlayed with vertical lines. See <http://dqd.com/~mayoff/border-bottom-bug/screenshot.png> for a screenshot. It seems to be related to the bottom-border setting of the <div> tag, because changing "dotted" to "dashed" in its style changes the pattern that fills the window. The real document where I first encountered this is at <http://dqd.com/~mayoff/doc/rfc2131/>.
This happens when the page is over 32000 pixels tall and overflows a signed short. *** This bug has been marked as a duplicate of 115526 ***