Accessibility fail.
As a blind user that requires a screen reader to interact with the computer, I don't have & can't use a mouse. (I can't see to aim it.) The icons are utterly useless & we *need* the plain text descriptions for our reader to read. No text means nothing to read & we have no idea WTF.
Sure the sighted folks using a mouse might be able to do the OnMouseOver hover+drag thing, but such actions are impossible if the user doesn't use a pointing device at all.
*Hands you a pint* Drink up, we can use the empty steins to bludgeon the MS devs with a clue. =-J