Fires when an item, spell or other entity that can be placed into an action bar slot is picked up onto the cursor.
Fires when an item, spell or other entity that can be placed into an action bar slot is picked up onto the cursor. In the default UI, this event causes the grid of empty action bar slots to be shown. (This grid only appears when something that can be dragged to an action bar slot is picked up, unless the "Always show action bars" option is enabled.)
