We are finalizing Drag & Drop functionality for TP 2.0. It is Atlas-based and we will share implementation details later.

Here are some basic guides for Drag & Drop functionality UI:

1. It should be clear that something can be dragged
2. When you drag something, it should be clear where the item can be dropped
3. If dragged item hovers droppable area, it is better to highlight the area. Highlighting ensures that this place is really droppable

If you follow these 3 rules, your D&D UI will be at least not bad, since application feedback is clear and guides user.

In TP 2.0 we have Iterations and User Stories. Drag & Drop fits perfectly for iteration planning process, when project manager can assign several user stories on iteration, see iterations plan and make changes.

On screenshot below we have three D&D areas: Backlog (left area) and two iterations (right areas). It is possible to take any user story from any area and drop to any other area. For example, you can take user story from backlog and assign it on Iteration #1.3 (right-top area). Then you may think that this is not the best place for user story, take it again and drop on Iteration #1.4 (right-bottom area). Or in the end you can take this annoying user story and throw it to Backlog. These three areas give user real flexibility and freedom.