I've found that going from a 1080 monitor to a 4K monitor has really put a damper on my ability to see the screen while using CS. In case other people are having a difficult time, I found a fix a while ago and I thought that I should share.
1-Find the main executable (DXP.exe)
a-Go to your search bar
b-Type CircuitStudio
c-Right-Click and select 'Open File Location'
d-Right-Click the shortcut and select 'Properties'
e-Click the button 'Open File Location'
2-Right-Click DXP.exe
3-Select 'Properties'
4-Click on the 'Compatibility' Tab
5-Check the box next to 'Override high DPI scaling behavior Scaling performed by"
6-In the drop-down, select 'System'
7-Press 'OK'
Now your CircuitStudio program will take on the scaling of whatever you have set up on your display settings.
Happy Birthday!