public void mergeDown(boolean createUndo) {
		if (layers.size() > 0 && activeLayer > 0) {
			if (createUndo) {
				addUndo(new CPUndoMergeDownLayer(activeLayer));
			}

			layers.elementAt(activeLayer).fusionWithFullAlpha(layers.elementAt(activeLayer - 1),
					new CPRect(width, height));
			layers.remove(activeLayer);
			setActiveLayer(activeLayer - 1);

			invalidateFusion();
			callListenersLayerChange();
		}
	}