It means that your FacesContext not longer available. The ID is corresponding to the FacesContext, which could be reached like this: FacesContext ctx = FacesContext.getCurrentInstance(); The lifecycle of this context act like the `@ViewScope`. So, an ID is generated for each HTML-Dialog which is called and is available as long the view is shown. For further information: [Javadoc FacesContext][1] But I am also not really confident with this. We have an a similar problem in our (pure JSF) project when we switch from one Dialog to another. The error occures just sometimes and in the background (the application seems to work). We suppose that there is a HTTP response sending by ajax from somwhere, as the faces context is already closed. I hope this information could help you in a way? [1]: http://docs.oracle.com/javaee/6/api/javax/faces/context/FacesContext.html

It means that your FacesContext not longer available. The ID is corresponding to the FacesContext, which could be reached like this: FacesContext ctx = FacesContext.getCurrentInstance(); The lifecycle of this context act like the `@ViewScope`. So, an ID is generated for each HTML-Dialog which is called and is available as long the view is shown. For further information: [Javadoc FacesContext][1] But I am also not really confident with this. We have an similar problem in our (pure JSF) project when we switch from one Dialog to another. The error occures just sometimes and in the background (the application seems to work). We suppose that there is a HTTP response sending by ajax from somwhere, as the faces context is already closed. I hope this information could help you in a way? [1]: http://docs.oracle.com/javaee/6/api/javax/faces/context/FacesContext.html