Connection from Win 10 to Ubuntu 18.04 weird connection

Weird connection happens when I connect from Win 10 to Ubuntu 18.04 in the same LAN. I can make the connection. I can move the mouse and click on the remote desktop. However, it seemed that all traces of mouse operations are left there without disappearing. So I can barely do anything with the remote desktop. For example, I right click the mouse and tne menu shows up, but after I released the right key, the menu remains. 

However, for the same pair of computer, it works fine if I connect from Ubuntu 18.04 to Win 10.