Metadata editor does not notice logout

[matthias-ronge]

After lunch, I came back, had left the metadata editor open. I can click around but nothing really happens:

Judging by the outputs in the browser console, the Tomcat seems to want to perform a redirect on the login screen, but that does not happen:

Goal: When the session is gone, the metadata editor should bring the user to the start page.

[solth]

This could probably best be achieved as described here: https://stackoverflow.com/a/2544766/5467214