/*
Returns a cluster that contains an addin with the given id or null if no cluster contains this id
function findClusterByAddinId(id) {
        var i, j;
        var clusters;
        for (j = 1; j < arguments.length; j++) {
            clusters = arguments[j];
            for (i = 0; i < clusters.length; i++) {
                if (clusters[i].containsAddin(id)) {
                    return clusters[i];
                }
            }
        }

        return null;
    }