Linden Lab added Cut & Paste operations to the inventory floater and for some reason made them work in the style of a text editor. Cut objects would vanish and reappear when pasted. Sequential cut operations results in inventory items moving to the trash.
Inventory Cut & Paste in Catznip works the way you would expect from file manager. Cut items are marked and moved on Paste. Sequential Cut operations changes the selection. No inventory is ever moved to the trash.