I want my application to change the program which should be launched if ie. a .jpg (in the HKEY_CLASSES_ROOT) is launched. The *.jpg and *.jpeg items in the registry references the jpegfile-class, but when I change the value of the default application to open the file, the old default is still launched, but not my program. (I set the value in jpegfile/shell/open/command/ to the path of my application.)

In firefox, the right-click menu etc the choice of default viewer will show that my application should be launched, but it isn't.