'Updates the tip based on user cursor movement.'

def _cursor_position_changed(self):

    cursor = self._text_edit.textCursor()
    position = cursor.position()
    document = self._text_edit.document()
    char = to_text_string(document.characterAt((position - 1)))
    if (position <= self._start_position):
        self.hide()
    elif (char == ')'):
        (pos, _) = self._find_parenthesis((position - 1), forward=False)
        if (pos == (-1)):
            self.hide()
