Updated the SwingController's openURL method so that the URL connection and subsequent file download happens off the AWT thread. The method was also reworked to show a ProgressMonitorInputStream dialog to give the end users an idea of how long the file will take to download.
The message property viewer.dialog.openURL.downloading.msg=Downloading has been added to the default message but not to the other message translations at this point.
Marking as fixed.