Copyright (c) 2005 Claudio Grazioli, http://www.grazioli.ch

This code is free software; you can redistribute it and/or modify it.
However, this header must remain intact and unchanged.  Additional
information may be appended after this header.  Publications based on
this code must also include an appropriate reference.
 
This code is distributed in the hope that it will be useful, but 
WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 
or FITNESS FOR A PARTICULAR PURPOSE.

Thanx for contributions to this ReadOnlyComboBox to Alexandre Cunha, Brasil.