EDIT

Utilizing the browser history back function can lead to a lot of confusing when the popup windows are open at the same time.

The NavigationManagerBean should check for open popups in the current view. In case open popups are found a warning dialog should be shown. Which offers the following options:

• Cancel
• Close all popups and leave current view

Test for the dialog: "You are about to leave the current view while poup editors are open. You you wish to close all open editors in order to proceed?"

There is a ticket in the vaadin issue tracker related to this:

• https://github.com/vaadin/framework/issues/4555
• https://github.com/vaadin/framework/issues/4794