User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8b2) Gecko/20050617 Firefox/1.0+ Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8b2) Gecko/20050617 Firefox/1.0+ A float is placed via negative margin above an area of a box which has overflow:auto assigned. The text lines show a "step" when they hit the overflowed box. The problem is reproducible no matter if the box is currently overflown, showing a vertical scrollbar or not. On a Mac build, increasing the text size +1 was needed to reproduce the problem. [Mozilla/5.0 (Macintosh; U; PPC Mac OS X Mach-O; en-US; rv:1.8b2) Gecko/20050619] The testcase uses different fractional offsets for the boxes to make the problem more reproducible. Screenshots are attached in the testcase. Thanks. Reproducible: Always Steps to Reproduce: 1. increase text size +1 or -1
I'm seeing this too with build id 2005061903 Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.8b2) Gecko/20050619 The above nightly build renders the test URL better than Firefox Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.8) Gecko/20050511 Firefox/1.0.4 so I guess this isn't a regression. Opera and Konqueror render the test case correctly.
Created attachment 186879 [details] minimal testcase Minimal testcase where I can reproduce the problem on OS X. One might need to zoom in to see the problem.
Created attachment 186881 [details] Screenshot from minimal textcase Screenshot on OS X. I zoomed in (120%) to see the problem. Depending on users settings (font-size, resolution), this might not be needed.
Reproduced on OS X with Mozilla/5.0 (Macintosh; U; PPC Mac OS X Mach-O; en-US; rv:1.8b2) Gecko/20050620 Firefox/1.0+ (PowerBook) and the official Firefox 1.04. The problem only happens with block level elements that are taken out of the flow (float or positioning) and overlap (or are covered by) another block element. Stacking order is not important. On OS X at least, the overflow property must be set to 'auto' or 'scroll'. Overflow:hidden or overflow:visible (the default) doesn't cause this problem. I cannot reproduce the problem with Camino [2005062008 (v0.9a1)]
Created attachment 186895 [details] more minimal testcase with linux trunk build 2005062002, for some level of text zoom, the black text is 1 pixel too high within the blue div.
Ingo, if you're still reading, are you able to reproduce this bug in Firefox 3? I can only see some kind of flickering while the elements are redrawn, but the final rendering is fine for me. Even using the different zoom methods. The testcases work for me as well.
On OS X 10.5, all test cases work just fine, without any flickering. On Linux / Ubuntu 8.04, I did notice some flickering with page zoom. That might be worth its own bug if none exist (I think I've seen it with other pages).
Works fine for me now. Thanks.
All right, thanks for your feedback. -> WFM