Comment 1 for bug 157883

I think the reload repositories updates all the repositories and not just the newly added one.

If you suggest automatically removing the newly added repo when the reload is canceled, it would affect the following scenarios:

1. The user has a bad internet connection and reload doesn't work
2. The repository is down (but the user wants to keep it and reload repos later)

In your situation, you could always go back and remove the repo yourself using software-properties