Look like an update issue. The bean get the value from xhtml page ? If he get it try to replace this two line:
<p:commandLink onclick="PF('dlg3').show();" process="@this" actionListener="#{messageBean.init(message)}">
<p:dialog header="Message" widgetVar="dlg3" showEffect="explode" hideEffect="bounce" resizable="true">
by :
<p:commandLink onclick="PF('dlg3').show();" update=":form1:dlg3" process="@this" actionListener="#{messageBean.init(message)}">
<p:dialog header="Message" id="dlg3" widgetVar="dlg3" showEffect="explode" hideEffect="bounce" resizable="true">