White box on turned off layers

Hi all.

Im a new user to catalyst (as in i used it for the first time last night in my living room) and i was just wondering, if i ahve layers turned off (say i only turn on 4) the layers not turned on (eg the other 8) they all show a white box on the output.

Why is this?

Thanks.

Hamish

The red buttons on the right are not switching the layer on/off , the just show/hide the layer .

To turn off a layer you need to DO NOT assign any Mix ( yellow buttons )

Link to this one for more info :

http://chaldee1.gotadsl.co.uk/~richa...ead.php?t=1467