update-manager 1:0.196.7, Ubuntu Trusty
1. Launch Software Updater.
2. Begin the installation of updates.
3. While updates are being installed, close the window.
What happens: The window closes, but updates continue installing. This is confusing, because it means you can't tell when the updates have finished, or why your computer is still running slower than usual. And it means you won't be prompted to restart if necessary at the end.
(If you try to undo your mistake by reopening Software Updater, it appears as only a title bar, bug 1297132.)
What should happen: Like any dialog or progress window, Software Updater should never have a close button in the first place. Exiting is handled by more explicit buttons, depending on the situation ("OK", "Cancel", "Remind Me Later", "Restart Later"). <https://wiki.ubuntu.com/SoftwareUpdates#Installing>
Fixing this bug would also fix bug 1251623.
Hi,
I wanted to contribute trying to fix this bug, but apparently it is not reproducible anymore on Ubuntu 17.04. Close button is still visible, but, once clicked, the update process is interrupted and it starts from the beginning once Software Update is started again.
Looking into the code (InstallAptBack