'Switch to the first window on prev column'

def cmd_left(self):

    c = self.current_column()
    cidx = self.columns.index(c)
    if (cidx == 0):
        return
    cidx -= 1
    c = self.columns[cidx]
    if (c['mode'] == 'split'):
        self.group.focus(c['rows'][0])
    else:
        self.group.focus(c['rows'][c['active']])
