void combineRois(ImagePlus imp, int[] indexes) {
		ShapeRoi s1=null, s2=null;
		ImageProcessor ip = null;
		for (int i=0; i<indexes.length; i++) {
			Roi roi = (Roi)rois.get(list.getItem(indexes[i]));
			if (!roi.isArea()) {
				if (ip==null)
					ip = new ByteProcessor(imp.getWidth(), imp.getHeight());
				roi = convertLineToPolygon(roi, ip);
			}
			if (s1==null) {
				if (roi instanceof ShapeRoi)
					s1 = (ShapeRoi)roi;
				else
					s1 = new ShapeRoi(roi);
				if (s1==null) return;
			} else {
				if (roi instanceof ShapeRoi)
					s2 = (ShapeRoi)roi;
				else
					s2 = new ShapeRoi(roi);
				if (s2==null) continue;
				s1.or(s2);
			}
		}
		if (s1!=null)
			imp.setRoi(s1);
	}