>Well, I have tried in a Listbox and a Combobox (VFP 6.0 & VFP 7.0) placing back slashes and the items are not disabled.
>
>Are there any properties to be changed?

No, I was wrong. The disabling in this manner doesn't work with the rowsourcetype=fields or alias. I know it works with type 0, 1 and 5 (none, data, array). Here's sample code I tried (works):

this.RowSourceType= 1
Select * from ..\data\names;
	into cursor temp readwrite
replace cDesc with "\"+cdesc for cGroup="pos"
Scan
	this.AddItem(Alltrim(cDesc))
endscan

Try this with your table, your fields and condition. This code is in listbox.init.