I would guess that it's either a problem with either the WPF font cache or hardware acceleration.
To clear the WPF font cache, follow these instructions:
- Ensure Visual Studio is closed.
- Press Win + R to access the Run... dialog.
- Type Services.msc, and then click OK.
- Right-click Windows Presentation Foundation Font Cache 3.0.0.0, and then click Stop.
- Press Win + R to access the Run... dialog again.
- Copy and paste %windir%\ServiceProfiles\LocalService\AppData\Local then click OK
- Find Fontcache3.0.0.0.dat and delete it
If that doesn't work then I would suggest temporarily disabling hardware acceleration in Visual Studio. If you go Tools -> Options... -> Environment -> General there is a checkbox that controls it. If disabling it makes a difference then see if the problems return if you re-enable it. Also try toggling the Enable rich client visual experience setting.