On IRC this evening somebody found it hard to find the options to edit a specific file type. The KCM is a mess unfortunately but I told him that you could edit specific file types directly from the properties dialog.
That button is hard to spot, though, which I also often found annoying. It is neither labled nor does it stand out as “button”.
This patch solves that issue.

It is in need of discussion whether the label itself should stay but the button definitly has to look like a clickable target.

Comparison screenshot: privat.broulik.de/filedialogpatch.png (this screenshot is from the initial attempt where i forgot the capitalization :P)