Consider a wiki site with various headlines and you want to link to a specific one ("critism" e.g.). When the site is named "GreatProduct" you'll do so by using the anchor links and create a link to GreatProduct#critism with the link tool. This creates the following wikitext: [[GreatProduct#critism]].

In the page this is correctly shown as a normal link later, however in the editor is it displays as a black link as if it would (only) "link" to the same site (aka [[GreatProduct]])…