"Propose for merging" for development focus suggests merging into itself

1. Go to the branch page for a development focus (for example, at the time of writing, <https://code.staging.launchpad.net/~ubuntu-installer/wubi/hardy>).
2. Click "Propose for merging".

What happens: The default "Target branch" is the same branch that you're proposing for merging. If you click "Register", you get an error: "The target branch cannot be the same as the source branch."

What should happen: Launchpad shouldn't suggest that I merge a branch into itself. If I'm proposing to merge the development focus into something else, the radio buttons and the "Other:" label should not be present: "Target branch:" should consist only of a text field.