Vnc can not right click.

What to you mean exactly? NOVNC from an VM? What guest OS? Console on the right side of the webinterface, or console on the middle (tabs)?
 
When I connect Windows KVM via VNC, I can not use mouse right click. Left click works fine.
Have you tested it with the console button on the right side of the PVE Webinterface? There opens novnc in an extra windows.
 
I am talking about that window already..
Ok, i tested this with us PVEservers. With the console at the TAB it works fine and with the button on the right upper corner it works also fine. With Wind7 and 2008r2 2012r2 Server.

Hmm... maybe it is depending on your webbrowser. I know, MS Internetexplorer or Edge do not work corectly with novnc. Only Firefox and Chrome can to this for you. Or you use Spice with virt-viewer, this works with every browser. But spice no good idea when you use it over the internet.