Domoticz

I have Philips Hue White lamps. Seperately the appear as dimmer switches (Lighting 2/AC) in Domoticz, as they should be.
But as a group (called 'room' in Hue) they appear as a RGBW dimmer switch (Lighting Limitless/Applamp/RGBW), which is silly, as it are just dimmable LED-lights.

How to change the RGBW-switch to a normal (non-RGB) dimmer switch?
I tried selecting 'white' instead of 'RGB' next to the colour palette in the switch edit screen, but that doesn't work.

Does anyone know how to change it?

And the group are all white lamps? If you added one or more rgbw lights the group will be that.
If they are all white lamps, it's a bug and you should post it here: https://github.com/domoticz/domoticz/issues

To you question of change. Do not think you can change that, it's not a virtual sensor. I could be wrong, can't check, no domoticz, it crashed

Yes, it are all White lamps. In the Hue-app itself the group also shows just a slider

best thing to do is open an issue on Github https://github.com/domoticz/domoticz/issues and describe it there