It behaves the same way in Chrome. It sounds like I can work around at least some of this behavior via JavaScript and HTML5 drag and drop support (ala
https://www.html5rocks.com/en/tutorials/dnd/basics/), although I'm not yet certain that will provide exactly what I want. Google searches haven't turned up anything definitive yet, unfortunately. Does HTML5 and JavaScript seem like the most reasonable approach? Not sure if I'm missing any other possibilities.