In the first case on the quoted test page, there is a table with two paragraphs containing two floated images, one left, one right. This is followed by some text in a CENTER element, which somehow ends up pushing the right image off the screen, causing horizontal scroll. In the second case, the table code has been removed, and now the centered text sometimes overlaps the right image, and sometimes the right image becomes invisible. These errors are simplified from the following page: http://www.bath.ac.uk/%7Een8dms/anime1.htm

Note. The overwrite problem only seems to occur if the page has been changed since the last time it was accessed. Feel free to make a local copy of the page to test with, if this is indeed the case.

The problem turned out to be (a) the code was counting twice the impact of floaters for table sizing and (b) not rendering things when it should. I've fixed both.

Bugs reported above are fixed. Some layout remain, and have been reported as bug 4204.