I am having the same issue.
I set the ReadOnlyStyle CssClass to "ReadonOnlyStyle" a Style I set in my CSS file as.
I set the RadTextBox to ReadOnly.
Below is the rendered HTML.
And the background color does not change.
If i explicitly set the BackColor Property of the RadTextBoxes ReadOnlyStyle it works just fine, but not when i reference it via the CssClass Property. (And the CSS file is registered with the page and other styles are working just fine)
What am I doing wrong?
Also, is it possible to set this value in the webconfig so that it applies to all RadTextBox.ReadOnlyStyles?
Thanks,
~Patrick