He’s right – but he’s missed something too.
Very few of the Windows.Forms controls support a true readonly mode – the TextBox is the only common one. Other controls either don’t support it (Combobox) or require horrible tweaks (turning AutoCheck false on a CheckBox).
This results in many developers making their controls disabled instead of read only.
Trouble is, the semantics are different.
“Disabled” means “This isn’t relevant”.
“Readonly” means “You can’t change this”.
The distinction is important.
Fortunately, with WPF, most of the controls support a true Readonly mode that remains readable. In my book, that’s worth any four demos involving 3D form rendering.