Fix for GenericAudioProcessorEditor

[TheVinn]

class ParamSlider::valueChanged() should read:

        void valueChanged()
        {
            const float newVal = (float) getValue();

            if (owner.getParameter (index) != newVal)
                owner.setParameterNotifyingHost (index, newVal);
        }

Previously, it was only calling setParameter(), and the host would not get notified.

[jules]

Nice one, thanks!