I see horizontal (dark) lines across some iframes and images in several webpages, most notably on the current OS/2 trunk builds but also on current Linux GTK1 trunk builds. The three iframes in the example URL <http://tinderbox.mozilla.org/showbuilds.cgi?tree=SeaMonkey> show this behavior on both OS/2 and Linux when I scroll the whole page so that these iframes appear or disappear from the content area. I originally wanted to post this to bug 201198, but the horizontal lines that Hartmut and me see are dark and not white. Also that bug has various reports that to me already seem like a mix of different bugs. With my profile on the current OS/2 trunk I can see the dark stripes in Hartmut Krafft's examples (only on OS/2) but I do not see them in the original example of bug 210198 nor in the ones that Jon Barber or oliv posted in the same bug. Interesting is also that a fresh profile does not have any of these problems, but I didn't manage to find out which preference was responsible (it is none of the obvious ones like smooth scrolling or graphics resizing). (I looked for quite some time for a dupe but didn't really find the same behavior.)

Edit->Preferances->Appearance->Fonts: Is "Display resolution:" set to the same in the profile that works and one that doesn't?

Yes, set to "System setting" in both.

bug 201198 / bug 111176 are likely two versions of the same bug..

OK, for the iframe part of this, bug 111176 might be a dupe. Then the remaining image part seems to be OS/2 specific. Was probably stupid of me to file this in one bug it just looks so similar...

> ------- Additional Comment #3 From R.K.Aa. 2005-03-06 10:24 PST ------- > bug 201198 / bug 111176 are likely two versions of the same bug.. I would support that, although the 2nd title is better! Bug 111176 Mysterious black lines appear when scrolling the window Bug 285004 Horizontal lines in iframes and across images when scrolling

> ------- Additional Comment #3 From R.K.Aa. 2005-03-06 10:24 PST ------- > bug 201198 / bug 111176 are likely two versions of the same bug.. Wait, I was mistaken in my last post. Here's what I think: Here are the relevant bugs Bug 111176 Mysterious black lines appear when scrolling the window has references to a number of bugs, including: Bug 201198 White lines appear on images when scrolling slowly through page Bug 284986 Bad rendering of gif images with transparency (banding, stripes) when slow scrolling on/off a pane Bug 285004 Horizontal lines in iframes and across images when scrolling I believe the chat at bug 201198 has been about several bugs, and that bug 284986 is a specific example. I believe that 285004 is another example of 201198. I also think 111176 and 285004 are dupes (though 285004 has a better title!).

To confuse things a little bit more: I don't see *dark* lines when scrolling over images, but lines in the webpage's background colour. Usually, white lines. See attachment #176247 [details] attachment #176379 [details] attachment #176381 [details] Didn't notice the iframe problem, till now. I didn't change the profile, will have to test on another box. One thing I can say for sure: the problem is absent in Mozilla/5.0 (OS/2; U; Warp 4; en-US; rv:1.7.3) Gecko/20040918 and present in 1.8b2. Hartmut

OK, I found the preference that causes the dark lines on the tinderbox page. It is user_pref("font.size.variable.x-western", 13); or Edit -> Preferences -> Appearance -> Fonts -> Proportional Size. Any other odd size >12 also causes stripes in the three iframes when scrolling while even sizes work fine. This was on OS/2, will try on Linux GTK1 later. Setting an even font size also seems to "fix" the problem on Hartmut's example page <http://www.wetter-zentrale.com/topkarten/tkavnmgeur.htm>. Btw, this is different from bug 111176 then, with even font sizes I continue to see the black lines on the collapsed border example there.

OK, the tinderbox iframes show exactly the same behavior on Linux trunk (GTK1), while the weather graph never shows lines.

The minimal useful testcase for the case of stripes in the iframe. float can be either left or right but not none, I tried different values of margin-top but only 0.5em shows the stripes. The font size in preferences has to be set to an odd number >12 (i.e. 13, 15, 17).

This shows the iframe problem with the minimal testcase with Mozilla/5.0 (OS/2; U; Warp 4.5; en-US; rv:1.8b2) Gecko/20050313 The stripes only happen when scrolling upwards, they are densest when moving the scrollbar handle, while they are larger using the scrollmouse. I guess every time the content area is refreshed, one line gets added.

Hmm, can anybody else reproduce on Linux? I do see it with my normal GTK1 build on my work machine (RedHat 7.3 based) with Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.8b2) Gecko/20050314 but not on a Fedora Core 1 based laptop, even if using the same Mozilla binaries. Can this be a bug in the XFree version or driver? If so, I tend to mark this bug OS/2 only.

Marking OS/2 only and confirming, several people from the newsgroup have reproduced this using OS/2.

Oh, I changed from All to OS/2 because I tried the same GTK1 build on several Linux machines now and can really only reproduce this on one of them (which sometimes acts weird in other respects as well).

Hmm, tried again just now with Mozilla/5.0 (OS/2; U; Warp 4.5; en-US; rv:1.8b4) Gecko/20050726 SeaMonkey/1.0a and I don't get stripes any more, neither on the tinderbox page, nor the testcase attachment, nor with Hartmut's wetter-zentrale example. And in spiegel.de images I haven't seen this either in the last few weeks. If there are no other observations I will mark this one WORKSFORME soon.