controlDown control not working

Code:

allchannels_enabled = ADDON.getSetting('allchannels.enabled') == 'true'



def onAction(self, action):

    if action == ACTION_MOVE_DOWN:

        if allchannels_enabled:

            self.button1 = self.getControl(4127)

            self.button2 = self.getControl(4131)

            self.button1.controlDown(self.button2)

Code:

<control type="grouplist">

    <!--ROW 1-->

    <control type="group">                  

        <control type="button" id="4127">

            <description>Channel Button 1</description>

            <posx>0</posx>

            <posy>0</posy>

            <width>350</width>

            <height>34</height>

            <visible>true</visible>

            <texturefocus>channels_bar1.png</texturefocus>

            <texturenofocus>changelang_yellow.png</texturenofocus>

            <label>channel 1</label>

            <font>Font_Bold25</font>

            <textcolor>0xFF000000</textcolor>

            <disabledcolor>0xFFFFFFFF</disabledcolor>

            <align>left</align>

            <aligny>top</aligny>

            <pulseonselect></pulseonselect>

            <onclick></onclick>

            <onfocus>-</onfocus>

            <onup>2</onup>

            <ondown>3</ondown>

            <onleft>1</onleft>

            <onright>1</onright>

        </control>



    <!--ROW 2-->

    <control type="group">                  

        <control type="button" id="4131">

            <description>Channel Button 2</description>

            <posx>0</posx>

            <posy>0</posy>

            <width>350</width>

            <height>34</height>

            <visible>true</visible>

            <texturefocus>changelang_yellow.png</texturefocus>

            <texturenofocus>channels_bar1.png</texturenofocus>

            <label>channel 2</label>

            <font>Font_Bold25</font>

            <textcolor>0xFF000000</textcolor>

            <disabledcolor>0xFFFFFFFF</disabledcolor>

            <align>left</align>

            <aligny>top</aligny>

            <pulseonselect></pulseonselect>

            <onclick></onclick>

            <onfocus>-</onfocus>

            <onup>2</onup>

            <ondown>3</ondown>

            <onleft>1</onleft>

            <onright>1</onright>

        </control>

</control>