Renaming a page to include '/' character creates two pages, the original is lost

When you rename a page e.g. "My page is green" to "My page is green/red" you get two pages: "My page is green" and "red".

The problem is that you loose data, i.e. the contents of the original page. Also in FAQ module, after renaming a FAQ item page, you can't either delete or edit the entry. The link leads to the first part of the page title (the one before /) but it does not exist so you can't delete. The title on the FAQ list is however full with "/".