Domoticz

I'm controlling 3 433MHz receivers via Domoticz and I bought this switch to turn them all on and off.

First I tried to add the switch as sub/slave device for one of the receivers. In the Domoticz UI I see the receiver go on/off when I use the switch, but in reality the light isn't turned on or off at all, which is weird right?

So now I'm using a dzVents script to control the receivers via the switch, which works fine, but there's a delay of 2 ~ 3 seconds between a using the switch and before the first light is switched. Why is there such a long delay?
And shouldn't sub/slave devices be the way to go for the scenario?

Thanks for the help!

Any1?

A sub/slave device only updates the status of the master switch in the GUI of Domoticz. It does not send a signal.

So for what purpose are sub/slave devices used then? I don't understand at all...

If you have a transmitter that is controlling a receiver directly, you want Domoticz to change it in the GUI too. But it must not send a signal, because it could switch the receiver again. In this scenario you set the transmitter as a slave. This info used to be in the manual, but I cannot find it anymore.

EDIT: it is in the manual, page 28.