I've noticed that the NumberField option does not respect the check parameter. The font is darkened, however, you can still interact with the option item despite the check cvar being disabled.
example instructions:
1) download the attached .pk3
2) open the "My Cool Menu" menu,
3) toggle the "test enabled" option,
4) mess around with the "test number" option despite the option item being darkened. You cannot alter the "test boolean" item while "test enabled" is off.