Fails in many situations including major ones like Facebook and Twitter. Even here on mozilla.org it fails to operate correctly on some elements.

The other major issue it has is that it continues to operate inside textareas so that reordering text/links with the mouse results in a search/link opening. In the default situation it blocks the text from being moved as well so it's actually breaking the expected behaviour.

On the plus side it restored my tab opening preferences for the most part. The ordering of tabs is backwards though so if you drag multiple links the order is Last->First when intuitively it should be First->Last