So when you click the internal link button on media wikis it pastes in [[link title]] Which I interpret to mean [[<internal link> <title for your link>]] But the syntax for this is is actually [[<internal link>|<title for your link>]] I reckon it should say [[<link title>]] rather than [[link title]]. Because as it stands it is not consistent with what the external link button offers up. which is [http://www.example.com link title] So for consistency the external link one could actually be [http://www.example.com <link title>]
or maybe [http://www.example.com LinkTitle] and [[LinkTitle]]
I have had many a frustrating moment getting my internal links to display properly when I followed the suggestion offered up by the button. Consider changing this in media wiki.
PS I use the userbase.kde.org wiki
mediawiki-l@lists.wikimedia.org