Disabled fields look different on different forms.

Steps to reproduce:

1. Go to Users -> Authentication -> HTTP settings tab
2. Check the appearance of disabled fields (field parameter "disabled"), looks OK
   
3. Go to Users -> Users -> Edit "guest" user
4. Check the appearance of disabled fields (field parameter readonly="readonly")

Result:

values in the fields are black, only the background is gray
Expected:
the same view as in HTTP settings tab, values are gray.

The same in some other places. For example, in inherited form of Graph or Graph prototype.

Should be checked in the entire UI.