When I launch any Mac application via Parallels Access, the applications do not use the full screen of the iPad.
- My Mac has Retina display.
- Parallels Desktop is installed on my Mac.
When Parallels Access connects to your remote Mac it automatically resizes the Mac screen to 1024x768. However it was discovered that such resolution is unusable on MacBooks with Retina with Parallels Desktop Virtual Machines running, because a lot of Graphic User Interface element inside the Virtual machine (Guest OS) will not fit the screen.
So the decision was made to set bigger screen resolution in that case.
The side effect of that change was that the bigger resolution does not fit well the iPad's screen, that is why the black areas can be seen on top and bottom of iPad's screen when working with Mac or Virtual Machine's applications via Parallels Access.