int getSelectionCount() {
		// FIXME mth 2003 11 16
		// very inefficient ... but works for now
		// need to implement our own bitset that keeps track of the count
		// maybe one that takes 'model' into account as well
		if (empty == TRUE)
			return 0;
		int count = 0;
		empty = TRUE;
		for (int i = viewer.getAtomCount(); --i >= 0;)
			if (bsSelection.get(i) && (bsSubset == null || bsSubset.get(i)))
				++count;
		if (count > 0)
			empty = FALSE;
		return count;
	}