I've thought about doing this, but honestly I'm not sure you really gain much in terms of speed. You'd have to have the token selected already, then drag and drop the roll result onto the bubble you wanted it to modify. Then it would open up the textbox witht he number filled in already, and put your cursor at the beginning of the text box so you could hit Enter for "set" or type "+, Enter" or "-, Enter" to add/subtract the value. So, I'm not sure how much that would really gain you versus just clicking on the bubble and then typing "34" or "+34" and hitting Return. In fact it might be slower since you'd have to do "fine tracking" with the mouse twice (once to select the roll result, once to drag it on the bubble) versus just once with the click and enter manually method, and typically using the mouse is the slowest part of any interaction...