Ok... this is apparently "by design"
http://support.microsoft.com/default.aspx?scid=kb;en-us;309338&Product=NETFrame

I have no idea why this was designed in the first place. Surely it's something useful to have!?!? Any thoughts???

Well... the workaround was to register a startup script that disables the items that I choose. What a pain! Something like this shouldn't be such a mission... but then again, I could well be doing something wrong. The problem is that information is lacking on this topic!! No info found on either Google or Microsoft Search... (and yes, I did use Microsoft Search first ;)

I also had a look around and couldn't find any good info :( Good luck!!!
Ps: MSN search is really not too bad (y)!!

There is no neat workaround, unfortunately. The neatest way that I know of is to inherit from the List control and work with the renderings yourself. Ie: override RenderControl and iterate through each item to output the correct HTML.

Thanks... I tried that, but sadly ListItem is a sealed class... no inheritance allowed. Bugger!

Nah. You got me wrong here. Don't inherit from the ListItem class -- inherit from the List control(s).

Aaah.... will give that a try. Thanks!

Ok... if anyone still cares... I found a better way of doing this. I must've been doing something wrong with the HtmlSelect control, because is you use item.Attributes.Add("disabled", "disabled") then it DOES in fact render to the client.

I really do feel that this should've been built as part of the DropDownList WebControl... surely this would be a better way of doing it?

If anyone finds info on why it was designed out, please post it here... I'm sure there's a good reason, just can't think of it right now.

I've found that the htmlselect attribute still won't render if it is contained in another control such as an ASP tablecell. That might have been the problem.

According to http://support.microsoft.com/default.aspx?scid=kb;en-us;309338&Product=NETFrame it has something to do with "expando" attributes being supported in the html control but not the web control.