After reading your posting a little closer I realize that I was mistaken, since you specifically mention a hotkey. You should, ofcourse, look in the OnPush trigger of the menuitem of said hotkey. If this hotkey has been applied to the standard fuctionality, “Explode BOM” then you should look in C/U 63 (Not C/U 51 which is used to explode BOM’s within BOM’s)