Here's what I did:
1. Created a new skin based on Hay using the Online Visual Style Builder.
2. Changed the background colour of the input control in read only state.
3. Downloaded and extracted the modified style to my skin directory.
These lines have been added to the CSS file:
Using Firebug to inspect I see this rule has been crossed out:
And this rule is in effect (except for the border-color)::
How can this be fixed? When I uploaded the zip file I noted the style tool did not recognize the change. The textbox is simply declared as: