Hallo,
firstly I love the folder size shell extension. I think that this is a very good example in programming a shell extension for Microsoft operating systems. Because of discarding some interfaces in Vista is unfortunately an another task of a challenge.
Your language support is exemplary. In spite of I have some suggestions for the folder size service:
Display Name: Ordnergröße-Berechnungsdienst
Description: Zwischenspeichern der Größen aller Ordner für den Explorer. Dieser Dienst überwacht alle Größenänderungen von Ordnern und aktualisiert den dazugehörigen Zwischenspeicher.
The display of your applet in the configuration panel is a little bit dissorted. I think, there are some problems with the alpha channel of your icon. Why you could not use the standard folder icon in the shell32.dll?
There is another folder size extension on the marketplace since over ten years ago. But I believe, that this extension is now not supported yet. It is from "Space Dolphin" version 3.2. The last release is from 1998. He has realized the folder size extension in an additional folder tab of the property dialog for drives and folders. My greatest wish will be the integration of this functionality in your folder size extension solution. Because I believe, that this interface is furthermore supported in Vista, you have a partial solution for your vista problem.
With best regards,
Dr. Heiko Voss