Unchecking or checkmarking sources in Software & Updates are not always possible

[Harald H.]

Reproduce:
- Open "Software & Updates"
- Select the tab "Ubuntu Software"
- Click on one of the checkboxes under "Installable from CD-ROM/DVD"
- If you are asked for authentication, cancel out of the window and try clicking on the checkbox again

Observe that you are not always asked for authentication and therefore not always able to change the options.

The bug is not reproducible for the checkboxes under "Downloadable from the Internet" on the same tab, but it is reproducible on the tab "Other Software" which has a similar checkbox list as "Installable from CD-ROM/DVD".

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Paul White (paulw2u)]

Thank you for taking the time to report this bug and helping to make Ubuntu better. This particular bug has already been reported and is a duplicate of bug 1727908, so it is being marked as such. Please look at the other bug report to see if there is any missing information that you can provide, or to see if there is a workaround for the bug. Additionally, any further discussion regarding the bug should occur in the other report. Feel free to continue to report any other bugs you may find.