I've seen problems with blank dialog boxes in a couple of instances. One was running in a VMWare Client after a Windows update, and the other was on a laptop running an Intel integrated video card.
From my research, it appears to be a problem with the WPF Hardware Acceleration. The only way I've found to fix the issue is to disable it for WPF applications. The settings can be created or modified by accessing the values directly by using the Windows Registry Editor.
Disable Hardware Acceleration Option
HKEY_CURRENT_USER\SOFTWARE\Microsoft\Avalon.Graphics\DisableHWAcceleration
The disable hardware acceleration option enables you to turn off hardware acceleration for debugging and test purposes. When you see rendering artifacts in an application, try turning off hardware acceleration. If the artifact disappears, the problem might be with your video driver.
The disable hardware acceleration option is a DWORD value that is either 0 or 1. A value of 1 disables hardware acceleration. A value of 0 enables hardware acceleration, provided the system meets hardware acceleration requirements; for more information, see reference page from Microsoft below.
ref:https://docs.microsoft.com/en-us/dotnet/framework/wpf/graphics-multimedia/graphics-rendering-registry-settings
