Consider these two cases: 1) data:text/html,%3Cdiv%20style=%22height:300px;width:300px;background-image:-webkit-repeating-linear-gradient(top%20left,%20red%2010%25,%20blue%2030%25);border:10px%20solid%22%3E 2) data:text/html,%3Cdiv%20style=%22height:300px;width:300px;background-image:-webkit-repeating-linear-gradient(top%20left,%20red%2010%25,%20blue%2030%25);border:10px%20solid%20transparent%22%3E The only difference is that 1) has a black fully-opaque border and 2) is transparent. In either case, we always draw in the 9-tile case (with the tiles behind the border). Most often, borders are opaque which would save us a bit of work to avoid drawing the full pattern.
<rdar://problem/10832889>
*** This bug has been marked as a duplicate of bug 37241 ***