We have a button which allows users to 'lock' a form. Users are not permitted to 'unlock' the form, so when pressed, we want the button to be disabled, so that the user receives appropriate visual feedback.
However, the customer reports that the greyed 'lock' icon suggests to them that the form is not locked, so we would like to display the button in a pressed state, but with the icon in colour, even though the button is disabled.
How do we do that, with the absolute minimum amount of overridden painting?