Create and Close a window with the button in ZK Framework

Hi to everyone!

I'm from Venezuela and a newbie in ZK's world, so I have the next code:

---

<fisheye label="Bienvenida" onClick="" image="../images/ico/landscape_bar/home.png">
<attribute name="onClick"><![CDATA[{
final Window w=(Window) Executions.createComponents("bienvenida.zul",null, null);
w.setClosable(true);
w.doEmbedded();
}
]]></attribute>
</fisheye>

---

It works perfect but when I do click over the button "Bienvenida" again, it creates the same window "Bienvenida".

I tried to put an Id in bienvenida.zul but when I do click over button "Bienvenida" again it gives me the next message:
"Not unique in ID space [Page rHxP_]:"

So, I would like to know if there is a way to create my window bienvenida.zul clicking on button "Bienvenida" and close it with the same button.

or something like this:

First click on "Bienvenida" = create bienvenida.zul
Second click on "Bienvenida" = close bienvenida.zul

If someone knows something about it please help me and I'll be pretty pretty grateful!

Best regards!