It is possible for item details to be displayed outside the visible screen space when hovering over an item at the lower positions of the list.
I encountered this at a resolution of 1920x1200 pixels (I did not check other resolutions).
screenshot to illustrate the problem (color reduced by me to save bandwidth):
Set the game resolution to 1920x1200 pixels fullscreen.
Do a search for items in the auction house until you get a list of results which spans several pages, preferably searching for items with lots of different magic properties.
Hover over the items in the lower positions of the pages and sooner or later you will encounter items where some of the details are cut off because of the item detail box not being within the screen bounds.
additional related feature request
While searching for equipment for a specific character (top left dropdown box) it would be nice if upon hovering over an item in the auctions an additional item detail box would be displayed for the item currently equipped by that character (like it is done when hovering over an inventory item inside the game itself).