Created attachment 598821 [details]
Image of it happening. Nightly window on left, extra CSS being loaded on right.
User Agent: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/535.11 (KHTML, like Gecko) Chrome/17.0.963.56 Safari/535.11
Steps to reproduce:
-Go on a website like 4chan.org, using 4chan X
-Use 4chan X to expand images in the thread
-Use Stylish to set all of the expanded images to position: relative so that their z-index can modified inside a reply, and set the z-index after that.
It renders poorly on Windows (haven't tested other operating systems). Scrolling with the image expanded causes the image to miss some parts, disappear entirely, or have bits of it flash in and out.
Does not happen in Firefox 12, or Chrom*. Doesn't happen with just set to position: relative. Only happens when both set to position: relative and setting any z-index.
The entire image is visible, doesn't have pieces missing when scrolling.
So on a whim I decided to see if the temporary fix that worked here fixes this issue:
The temporary fix being to add the CSS: "box-shadow: #000 0 0 0;"
This added in makes the image completely disappear, with no getting it back without removing that line. So the bugs are absolutely related even though that line has different effects.
Seems to have been fixed on its own with version 14.