Hi Raj,
Thank you for this, but as explained in the thread, I have no issues using CTRL 1-3 to switch between Mac desktops. The problem is that in Parallels 12, contrary to Parallels 11, it's impossible to assign a Mac Desktop to Parallels. Parrallels has its own desktop (called parallels desktop) which isn't controlled by CTRL 1-3. It was the same in Parallels 11 initially, but there was an option in Parallels settings that allowed to get Parallels assigned to a Mac desktop. This option in Parallels settings (assign full screen to OS X) is gone.
Please read my description in detail, and try to reproduce. The solution that Ajith provided is impossible because the settings are different in Parallels 11 and Parallels 12. The how to he linked to was from an old version of parallels, not 12.
By the way, I have assigned the Parallels app to the Mac desktop 2 only, but that doesn't pay any role when parallels is displayed full screen, unlike with version 11. The full screen Windows VM is assigned to a separate desktop (Parallels desktop) in V12 and cannot be controlled by CTRL 1-3.
Last edited: Nov 19, 2016