Just to confirm I can reproduce this 100% reliably in 18.10 and in Disco, as follows. Open Software & Updates and switch to the Other Software tab and click one of the checkboxes the window loses focus but the authentication dialog does not appear (I have checked it is not under another window). If however I click a checkbox on the Ubuntu Software tab then the authentication dialog does appear.
** Tags added: disco -- You received this bug notification because you are a member of Ubuntu Desktop Bugs, which is subscribed to gnome-shell in Ubuntu. https://bugs.launchpad.net/bugs/1734095 Title: Software & Updates not showing authorization popup [gnome-shell[N]: pushModal: invocation of begin_modal failed] To manage notifications about this bug go to: https://bugs.launchpad.net/gnome-shell-legacy-bugs/+bug/1734095/+subscriptions -- desktop-bugs mailing list email@example.com https://lists.ubuntu.com/mailman/listinfo/desktop-bugs