Comment 3 for bug 1607277

> This should work as usual. The LED should always reflect the "[ Ch1 ]" button in the LateNight
> skin. Is this true on your side?

Yes, this is true, unless some other function changes the led.

> This should transmit the current state of the CO to the LED.

No, Engine.trigger calls whatever javascript function is connected to a CO through Javascript, but it seems that it doesn't update GUI or doesn't send midi messages to update the leds mapped through XML

> If you uses engine.trigger("[EffectRack1_EffectUnit1]","group_[Channel1]_enable", value),
> both the mapped controller LED and the GUI LED should be updated. If this is not the case,
> it is a bug. Does it happen?

No, calling engine.trigger doesn't update the controller LED when that led is mapped through XML.

You can see how I had to workaround that here https://github.com/sblaisot/mixxx/blob/ba99922caa76415bf76b6048078db0ab6b232a58/res/controllers/Reloop-Beatmix-2-4-scripts.js#L479

I'll try to make a test mapping to demonstrate that.