DialogTextBoxPropertyEditor ignores PropertyGrid.IsReadOnly

I defined a property like this:

[Category("Starting Page Filter"), DisplayName("Valid Images")]
[Description("Path to images that match this template.")]
[Editor(typeof(DialogTextBoxPropertyEditor), typeof(PropertyEditor))]
public String ValidImagesStart
{
get
{
return _template.ValidImagesStart;
}

set
{
_template.ValidImagesStart = value;
SyncCOMObject();
}
}

I point the property grid to the object that contains this property. Everything works fine.

I add propGrid.IsReadOnly in the code behind and all the built in properties go to read-only mode as expected. The DialogTextBoxPropertyEditor items remain enabled.

Actually, its just the button thats not disabled.

[Modified at 08/25/2010 06:05 PM]