Mouse actions and shortcuts

Action	Result
Drag & drop	Move items between your inventory, a stash, the ground, the backpack and clothing slots
Shift + drag	Move half of the stack
Ctrl + click	Quick-move the item to the other open inventory
Alt + click	Use the item
Right click	Open the context menu
Drop on Use	Use the item
Drop on Give	Give the item to a player
Drag out of the inventory onto the game world	Place the item in the world (if it can be placed)
Amount box (between Use and Give)	How many items a drag moves (0 = the whole stack)