Since Magnolia 5.5.6 when exporting content in XML format, it's open in the same browser's tab whereas when YAML is selected, exported file downloads as expected. (See attached picture)

Steps to reproduce in Magnolia 5.6.6:

1. Enter admin central and go to configuration app
2. Select one of the nodes there an press export
3. Select XML format and press export

In Magnolia 5.6.5 it works ok.

After export XML (where we're in XML view of browser) of JCR browser app:

1. press back button of the browser
2. we get back to JCR browser app view with dialog overlay and also locked by this screen (screen shot)
3. refresh the page does not help, cancel button doesn't work, close button of the dialog also not responding. User must logout, switch to another app or close the app and open it again to get out of this stage

Expected result: just download the XML file as it is.

Tested in chrome and firefox.