Following up on my comment <https://bugs.webkit.org/show_bug.cgi?id=30754#c8> on bug #30754. There are some Windows-specific issues in our drag-and-drop code that we need to correct. For instance, a dragleave event is fired after a dragover event is fired, which is incorrect. The correct firing ordering should be dragover, drag, dragleave.
Created attachment 43392 [details] Layout test
Created attachment 43393 [details] Isolated Test Case For your convenience, here is an isolated version of the test case (that you can run in your browser) that references the associated webkit.org resources.