I have been fighting this problem with the overlay since steam updated their design. My problem lies with the buttons, they are extremely laggy and take seconds to register a click. Once the clicked tab is opened, i can do whaterver but the buttons are still bad.
This mostly happens in 3D games.

Any idea on how to fix this issue? i already tried disabling hardware acceleration, didn't work
Disabling Hardware Accelerated GPU Scheduling on windows is an option, but i don't think it would work either.