I had the same problem, look this solution.
The issue is due to large DPI setting at your PC. You can either reduce the DPI to 100% or use the below steps1. browse to %APPDATA%\PMDG\PMDG Operations Center2. Right-click PMDG Operations Center.exe and choose "Properties"3. Compatibility Tab4. Change High DPI settings5. Tick the Override high DPI scaling behavior And select Scalling performed by System