Yes, seriously. As far as I can tell, only paper, though I haven't tested it on too much. 

1. Drag vase in character inventory.
2. Accidentally drag it over paper while trying to place vase.
3. Crash.

___________________________________________

############################################################################################

ERROR in

action number 1

of Draw Event

for object InventoryScreen:

Variable <unknown_object>.skill(100132, -2147483648) not set before reading it.

at gml_Script_SpawnNewItem

############################################################################################

gml_Script_SpawnNewItem (line -1)

gml_Script_SpawnRefItem

gml_Script_ItemCanFill

gml_Script_ItemsCombinable

gml_Object_InventoryScreen_Draw_0