V6 Viewport Switch Delay

I use Rhino V6 (WIP) on Parallels with the latest MacBook Pro (AMD GPU). Other than in my regular V5 Windows suite (which I also use with Parallels, on the same machine) switching between Viewports (Perspective, Top etc.) is extremely delayed i.e. nearly impossible to work with. Happens when I double- or single-click the viewport tabs and click on the tabs at the bottom likewise.

Thanks for considering

Now that I switched from Parallels to VMWare Fusion, the problem has gone. VMFusion supports Open GL 3.3, Parallels only 2.1.
Another issue: VMFusion allows for Retina display (with some Mac Terminal tweaking). Result: Sharper display (good), slight viewport nav slowdown (not so good). So for now I’ll stay without Retina display.

Best, Horst