From Demetra Beta feedback: When dragging text to a new location, if you put the cursor just a little bit too far left (into the area where breakpoints and other annotations are) there is no indication (via the cursor image) that you are too far left and the drag fails silently. I end up having to pay too much attention to when the cursor is. Perhaps you could just allow the drag to succeed even if the cursor is a little bit into the left margin?