Rich Client Faces

Hello,
I have a problem with the messageDialog tag that duplicates javascript code in the selectionListener attribute into the generated v:events attribute (in v:init tag).

This code :
<v:messageDialog id="alerteDejaValide" visible="false" hiddenMode="ignore"
text="#{MessageBean.get['gestionDossier.message.CHANGEMENT_STATUT']}"
title=""
binding="#{DossierBean.refMessage4}"
defaultValue="Annuler_02"
selectionListener="return cover(event);#{DossierBean.modifierDossier}"
imageURL="$context/images/ico_avertiss.gif" height="150"
width="450" styleClass="avertiss" >
<core:selectItem itemValue="Confirmer_02" itemLabel="#{MessageBean.get['commun.texte.CONFIRMER_MAJ']}" />
<core:selectItem itemValue="Annuler_02" itemLabel="#{MessageBean.get['commun.texte.ANNULER_MAJ']}" />
</v:messageDialog>

Generates this one in the page source :
<v:init id="validerForm__alerteDejaValide" v:class="f_messageDialog" v:events="selection:return cover(event):return cover(event):return cover(event)|selection:submit" v:title="" v:text="Le statut du dossier va &ecirc;tre modifi&eacute; : veuillez confirmer ou annuler" v:defaultValue="Annuler_02" v:width="450" v:height="150" v:styleClass="avertiss" v:imageURL="/euroforms/images/ico_avertiss.gif"></v:init>
<script>//<![CDATA[
var _4=_rcfacesClassLoader.f_init("validerForm__alerteDejaValide");
_4.f_addAction("Confirmer_02","CONFIRMER",false,false);
_4.f_addAction("Annuler_02","ANNULER",false,true);
_4.f_openMessage();
//]]></script>

In fact, we can see this line :
v:events="selection:return cover(event):return cover(event):return cover(event)|selection:submit"

The Javascript function is :
function cover(evt) {
var value = evt.f_getValue();
if (value.indexOf("Confirmer") >= 0) {
hideMessageDialog();
return true;
}
if (value.indexOf("Annuler") >= 0 || value.indexOf("Fermer") >= 0) {
return false;
}
return false;
}

So it returns true or false and executes or not the next function in the same bloc of instructions.
The problem is that it generates a bug because of multiple submits.

How can I avoid this behavior of duplicated javascript code ?

Thanks a lot !