Can't rename wiki article to change case

If I try to rename an article in the Qt DevNet wiki to change the title case, I get an "article already exists" error. For example, if I try to rename Performace_of_foo_bar to Performance_of_Foo_Bar, I get an "Article with that name already exists" error. This makes it impossible for admins to harmonize title cap case without delete/create of articles, which would break article history.