File Previews on Windows
Seems like Microsoft has a mechanism to load preview handlers and preview documents similar to QuickLook on Mac.So we can query the available preview handlers from the registry. You pick one and select a file and we try to show a preview. You find those in the registry at HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\ CurrentVersion\PreviewHandlers. The handlers are listed with Class ID there (a GUID) and a name as value.
Also for file extensions like ".contact" you find a registry key like this: HKEY_CLASSES_ROOT\.contact\shellex\{8895b1c6-b41f-4c1c-a562-0d564250836f}. This key has a default value with "{13D3C4B8-B179-4ebb-BF62-F704173E7448}". And this value is the class ID for the "Windows Contact Preview Handler".
Maybe this helps a few people developing better Windows applications. The WindowsPreviewHandlerMBS class will be available with next plugin prerelease.
