Disabling Sorting how to do it???

Hi,
I'm very new to JS and active widgets and have been trying to get sorting disabled on the grid by following previous posts etc but with no success.
I've managed to disable resizing but cant figure out exactly how to disable sorting. Do you have a dummys example.
Is it possible to do it by using some statement like this ???
this.setSortProperty("index", null);


Many Thanks

//Disable sort
obj.sort = function(index, direction){
return true;
}