'Get module name from user and open it.
Return module path or None for calls by open_class_browser
when latter is not invoked in named editor window.'

def open_module(self):

    try:
        name = self.text.get('sel.first', 'sel.last').strip()
    except TclError:
        name = ''
    file_path = query.ModuleName(self.text, 'Open    Module', 'Enter    the    name    of    a    Python    module\nto    search    on    sys.path    and    open:', name).result
    if (file_path is not None):
        if self.flist:
            self.flist.open(file_path)
        else:
            self.io.loadfile(file_path)
    return file_path
