Teamviewer 12.0.82953 dual monitors

[Jab]

Hello all. 
I have just installed 12.0.82953 onto my rMBP running Sierra 10.12.6 and onto a Dell laptop running Windows 7.
Both have the notebook monitor and a second physical monitor attached to them and I connect successfully.  When I display both monitors of the Win 7 laptop they show only on the main screen of the Mac.

After searching the Net I find that they suggest using an option to pop the 2nd screen out but no option seems to exist in the view options.

So how can i get the 2 Dell screens shown on the relevant screens on the Mac & it's 2nd monitor.

Thanks, Jim