For multimedia files on Windows, there are usually two different shell commands for each of the file formats to be played back: "Open" and "Play". Both contain the same thing: a path to and file name of the application used to open the file, as well as any command line arguments required for the command, as well as all the other entries regarding DDE (in the case of VLC it's just "vlc" and "System" that are added for DDE).
The problem with VLC is that it doesn't set the "Open" command, but only the "Play" command. This means that some generic applications cannot find the application used to play some file types, because there is no "Open" command for this file type to be found in the Shell. A generic application using the API ShellExecute, for instance, should be able to use the "Open" command, and it should work. Unfortunately, when VLC is installed, and you allow it to associate itself with all of the file types it can handle, the "Open" command is removed from the Shell settings, leaving the file format without an application to handle it, as far as the generic application that uses the "Open" command is concerned, that is.
Is there a solution to this problem somewhere?