Clicking on Cancel or Authenticate did nothing. Clicking on Details worked normally (showing and hiding the details). When I clicked the close button in the top right corner the dialog was closed and the installation proceeded normally.
This was while installing the "Avahi Zeroconf Browser". I tried uninstalling it and installing it again, but then the problem did not occur, so it does not appear to be related to specific packages.
Yes! I did it. Here's the screenshot.
Clicking on Cancel or Authenticate did nothing. Clicking on Details worked normally (showing and hiding the details). When I clicked the close button in the top right corner the dialog was closed and the installation proceeded normally.
This was while installing the "Avahi Zeroconf Browser". I tried uninstalling it and installing it again, but then the problem did not occur, so it does not appear to be related to specific packages.