An application launched in OS X/macOS guest operating system in virtual machine does not work properly (graphical artifacts/issues) or cannot be started.
For example, working with any of iWork applications you cannot see the page content, which disappears after a few seconds from starting an application.
Or Mozilla Firefox window isn't scaled or Google Chrome interface isn't correctly drawn. The same for GitHub Desktop/Chrome applications, they're using Cocoa GUI framework.
Parallels Desktop does not support 2D or 3D acceleration in OS X/macOS guest operating systems (installed inside the virtual machine) because Apple does not provide an API for creating a video driver with 2D/3D acceleration support.
As a result there might be any kind of graphical artifacts or an application could behave incorrectly, even doesn't not work at all if the 2D or 3D acceleration is required for its functionality.
Without the required API there is no possibility to implement such functionality in its best. To check that it's indeed related to the lack of 2D/3D acceleration support do the following:
- Install the same application to your Host Mac OS computer.
- Restart the Host Mac OS in the Safe Mode.
- Start the application in the Safe Mode and check how it behave.
If the application in the Safe Mode behaves in a same way as in a Parallels macOS/OS X virtual machine it means that the application require 2D/3D acceleration for its functionality and will not work correctly without it.
In case you can see the same issue in the Safe Mode - it is a reason to contact Apple Technical Support.
In case in Safe Mode issue disappears, contact Parallels Technical Support.