public long getUndoMemoryUsed() {
		long total = 0;

		CPColorBmp lastBitmap = clipboard != null ? clipboard.bmp : null;

		for (int i = redoList.size() - 1; i >= 0; i--) {
			CPUndo undo = redoList.get(i);

			total += undo.getMemoryUsed(true, lastBitmap);
		}

		for (CPUndo undo : undoList) {
			total += undo.getMemoryUsed(false, lastBitmap);
		}

		return total;
	}