It is possible to open Debug window using ?debug in production mode

[TatuLund]

If you run Vaadin 14.7 / Vaadin 8.14 + MPR app running jetty:run -Pproduction and using profile settings as documented, Vaadin 8 will adopt the production mode setting correctly in the server side. However you can still open the Debug window using ?debug query parameter in the url when using non-root Routes. The debug variable is true in client side but production mode status is false in the server side,

Workaround is to force the debug to be false when root layout is attached.

	@Override
	public void onAttach(AttachEvent event) {
		if (event.getSession().getService().getDeploymentConfiguration().isProductionMode()) {
			event.getUI().getPage().executeJs("window.vaadin.debug=false;");
		}
	}

You can demonstrate this by checking server side production mode

https://github.com/TatuLund/mpr-demo/blob/dfe3ba7342e4b18567f9dec30d4fb40ffb934e52/src/main/java/org/vaadin/mprdemo/MyUI.java#L54

Complete demo

https://github.com/TatuLund/mpr-demo/tree/mpr-4