Steps to reproduce:
1) go to some plan source repository configuration
2) click 'add repository'
3a) set repository name, for example "aaa"
3) on the right: from the list select Mercurial repository
4) set repository URL to something like "aaa" (doesn't matter in this test-case)
5) select from "Web Repository" -> "Mercurial Web Repository" (you can leave the sub-select default)
6) click 'save repository' (on the right)
7) click again on "source repository" tab (like you would like to edit the plan
8a) there is no new repository - it disappeared
8b) while I expected it will wait for me there, my new "aaa" repository.

(note: if I don't select the Web Repository for that new repository -> all is good, I have my 'aaa" repo)