Created attachment 150833 [details] Test case To reproduce, open the test case, then open the Web Inspector in DOM tree mode, then close the Web Inspector, then reload the page (there may be other ways to reproduce the bug). After doing so, even after repeated reloading of the page, the second <div class="test"> gets both a width and a height of 100px, and gets borders on all four sides. Apparently findFromMatchedPropertiesCache() decides to copy from the style of the first <div class="test"> into the style of the second one, despite their writing mode difference.
<rdar://problem/11806873>
Looks like this was caused by <http://trac.webkit.org/r98542>.
The test case is confusing. What does the correct rendering look like? Inspecting the test changes (corrects?) the rendering but I don't see anything persisting over reloads. The cache is per-document so it shouldn't be possible.
(In reply to comment #3) > The test case is confusing. What does the correct rendering look like? Black upside-down L, no blue. > Inspecting the test changes (corrects?) the rendering but I don't see anything persisting over reloads. The cache is per-document so it shouldn't be possible. That’s a good start :-)