http://build.webkit.org/results/Apple%20MountainLion%20Release%20WK1%20(Tests)/r145999%20(8005)/inspector/elements/highlight-node-scaled-pretty-diff.html 2Uncaught exception in inspector front-end: TypeError: 'null' is not an object (evaluating 'node.getAttribute') [undefined:21]
Closing as invalid, as this bug pertains to the old inspector UI and/or its tests. Please file a new bug (https://www.webkit.org/new-inspector-bug) if the bug/feature/issue is still relevant to WebKit trunk.