Display Primefaces's OverlayPanel when the page loads

The page shows a Primefaces's overlayPanel when the target component (a commandButton) is clicked on:

<p:commandButton id="inputBtn" value="Choose a data source" type="button" action="#{dataImportBean.oAuth}"/>
 
<p:overlayPanel
 id="overlaypanel1"
 for="inputBtn"
 dynamic="false"
 widgetVar="inputChooser"
 >
// contents of the overlay panel
</p:overlayPanel>

I would need the overlayPanel to be displayed when the page loads, without the need to click on the target commandButton.

The use case is: the user had the overlayPanel opened but an oAuth flow made the user navigate away from the page. When the oAuth is completed the user is redirected to the page. However the overlayPanel is closed when the page loads, whereas I need the user to be brought back directly to the overlayPanel, for consistency.