Disable Drop Shadows in Windows 10
I don’t know why the windows drop shadows in Windows 10 are huge making it difficult to view the window behind it.
Disable the Drop Shadows
Go to Control Panel and click on System and Security, then System, and click the Advanced system settings link.
From here, go to Advanced tab and click the Settings button under Performance.
Find and uncheck Show shadows under windows and click Apply and OK.
The drop shadows will be removed.