All that is required to reproduce this bug is to go to www.pricepoint.com. Below the gray Search/Status bar, there should be a JavaScript menu with a black background and yellow text. It is supposed to react to mouseover events to select a subcategory. With OmniWeb 5.6 sneaky peek 4 (v611) and the nightly WebKit build, the menu just doesn't show up at all. There's a big blank space where the menu ought to be. With Safari version 3.0.2 (522.12), the menu does show up and functions as expected.
Confirmed as a regression with r24244.
Created attachment 15492 [details] reduction
<rdar://problem/5335694>
Committed revision 24457.