Problem refreshing browser window: when 'update all content' had failed, the widget kept showing progress.

Use case 1:
I ran 'update all content' on the docsite and it get being in process for hours. Bart said there was no activity on the server. I reloaded the page (shift reload button) and then the widget showed the message that 'update all content' had failed. This was on Tomcat.
The cause of the failure was that the doctypes had not been upgraded completely: inherited field where supplied, which is not required any more.

Use case 2:
I tested the problem of use case 1 locally. This was on Jetty. Failure was indicated after a few minutes. So no problem with refreshing the browser window.

Use case 3:
I ran 'update all content' on the docsite and it indicated failure after a few moments. However, the progress indicator kept running. After I reloaded the page with shift reload button, it had stopped. This use case is shown in the attached movie.