Using $("something > table:first") as a selector used to work fine, but in recent WebKit nightlies (and now the latest release of Google Chrome for Windows) it does not work. The URL shows an example; loaded in an older WebKit (e.g. Safari 4) and the latest shows the different behaviour (the first Table should have a black background). Hope this is actually a bug and this is the right component.
This should be fixed in the next nightly build. *** This bug has been marked as a duplicate of bug 38697 ***