Special characters in anchor links are converted to HTML entities

When I use the "Insert Link" dialog to insert a link to an anchor with special characters (e.g. german umlauts), the link text contains HTML entities.

Steps to reproduce:

1. Create a new empty page
2. Select "Insert --> Link" to display the link dialog
3. Select the "Advanced" tab on the left side
4. Enter the link: #Test für Anker

--> The auto-generated link text is: "Test f&uuml ;r Anker"
But it should be: "Test für Anker"