def createMainWidget(argv):
    """
    Function to create the main widget.
    
    @param argv list of commandline parameters (list of strings)
    @return reference to the main widget (QWidget)
    """
    from Tools.TRPreviewer import TRPreviewer
    if len(argv) > 1:
        files = argv[1:]
    else:
        files = []
    previewer = TRPreviewer(files, None, 'TRPreviewer')
    return previewer
