I can't paste in schematic design using Quartus Prime 16.0 (i'm using Win10)

Recently I confront a problem, when I use schematic design in Quartus Prime 16.0 sp2, I can't paste symbols, the paste operation is disabled (showed in bar a grey), no matter I copy or cut anything, they can not be pasted. Did anybody confront similar problems like me ?

Thanks very much.