def _currentLineExtraSelections(self):
        """QTextEdit.ExtraSelection, which highlightes current line
        """
        if self._currentLineColor is None:
            return []

        def makeSelection(cursor):
            selection = QTextEdit.ExtraSelection()
            selection.format.setBackground(self._currentLineColor)
            selection.format.setProperty(QTextFormat.FullWidthSelection, True)
            cursor.clearSelection()
            selection.cursor = cursor
            return selection

        rectangularSelectionCursors = self._rectangularSelection.cursors()
        if rectangularSelectionCursors:
            return [makeSelection(cursor) \
                        for cursor in rectangularSelectionCursors]
        else:
            return [makeSelection(self.textCursor())]
QTextEdit.ExtraSelection, which highlightes current line