Feature Tracker:
http://joomlacode.org/gf/project/joomla/tracker/?action=TrackerItemEdit&tracker_id=8549&tracker_item_id=31100

It would be great if this feature was available for the entire framework, not only in com_content and com_config.
I would like to add it on my own extension's Configuration.

@machadoug PR done, feel free to test

@Bakual, Nicely done!
Worked correctly.

Thanks for implementing it.

@Bakual,
Based on your changes I have tried to implement this in /libraries/joomla/form/field.php, getControlGroup() method, so it would be available for plugins as well, but I could not figure it out why it did not work.
Can you submit a Pull Request with that feature?

Here is what I've done, but it did not work.

    public function getControlGroup()
    {
        if ($this->hidden)
        {
            return $this->getInput();
        }
        $class  = '';
        $rel    = '';
        if ($showon = $this->getAttribute('showon')) :
            JHtml::_('jquery.framework');
            JHtml::_('script', 'jui/cms.js', false, true);
            if($this->formControl){
                $id = $this->formControl;
            }else{
                $id = '';
            }
            $showon = explode(':', $showon, 2);
            $class  = ' showon_' . implode(' showon_', explode(',', $showon[1]));
            $rel    = ' rel="showon_' . $id . '['. $showon[0] . ']"';
        endif;

        return
            '<div class="control-group'.$class.'"'.$rel.'>'
            . '<div class="control-label">' . $this->getLabel() . '</div>'
            . '<div class="controls">' . $this->getInput() . '</div>'
            . '</div>';
    }

Thanks for your help.

There is already a PR done by Marko D: #3127