Not a bug
In sprint planning mode: If I drag a story from the backlog to the current and then change my mind it still gets added.
1) Drag a story
2) Drop it back in the backlog pane (the right one).
Expected result: stay in backlog
Actual result: gets added to the sprint.
It is difficult to manual reverse that, because I have to hunt the current sprint for that story, and with no colors or other indications, it's really hard to know which story was that.
Customer support service by UserEcho