In r54084 I've noticed that right-clicking on a word does not select it before displaying the context menu. This behavior is standard system behavior on Mac OS X, and the lack of it is partially to blame for items being omitted from the context menu (eg, Copy. See bug 34360). This works correctly in a build of WebKit from earlier in the week.
<rdar://problem/7594376>
Fixed in http://trac.webkit.org/changeset/54133. https://bugs.webkit.org/show_bug.cgi?id=34400