ClientWindow - StoreWindowTreeEnabledOnButtonClick prevents defined onclick

Example:

<h:commandButton id="testButton" value="TestButton" type="button" onclick="PF('dlg1').show();" />

<p:confirmDialog id="dlg1" header="Basic Dialog" widgetVar="dlg1" minHeight="40" modal="true">
<h:commandButton type="submit" value="submitButton"/>
<h:outputText value="Resistance to PrimeFaces is futile!" />
</p:confirmDialog>

The original onlick is never called.