When editing the package sources list, apper will save edits as soon as I check/uncheck an entry in the list. My proposal is: 1. let the user make all the edits and save only when a confirmation button is pressed 2. put a checkbox to let the user choose if he wants to really save the edits as default setting for a future use, or only use the edits for the actual session. The second point is useful when you want to search and install a specific package from a updates-testing repository. At the moment I have to enable the updates-testing repository, install the package and then manually disable again the updates-testing.