The search field on http://developer.apple.com/ is not drawn with its top or bottom border in a locally-built debug build of WebKit r18251 with Safari 2.0.4 (419.3) on Mac OS X 10.4.8 (8L127). There is a highly suspicious SearchBoxFix() JavaScript method that may be doing Bad Things(tm), but I haven't investigated it yet.
Created attachment 11877 [details] Screenshot
NOTE: This may need a Radar bug if it's an issue with the web site, not the implementation.
<input type="search" style="height: 15px;"> or anything smaller than 15px makes the horizontal borders disappear.
See Comment #3 for reduction.
<rdar://problem/4887422> REGRESSION (SearchField): Search field on developer.apple.com not drawn with top/bottom borders (11848)
*** Bug 11890 has been marked as a duplicate of this bug. ***
Committed revision 18585.