public void mouseReleased(MouseEvent e) {
		ImageCanvas ic = imp.getCanvas();
		Rectangle srcRect = ic.getSrcRect();
		if (srcRect.x!=startingSrcRect.x || srcRect.y!=startingSrcRect.y) {
			// user has scrolled xy image
			int dy = srcRect.y - startingSrcRect.y;
			ImageCanvas yzic = yz_image.getCanvas();
			Rectangle yzSrcRect =yzic.getSrcRect();
			if (rotateYZ) {
				yzSrcRect.x += dy;
				if (yzSrcRect.x<0)
					yzSrcRect.x = 0;
				if (yzSrcRect.x>yz_image.getWidth()-yzSrcRect.width)
					yzSrcRect.y = yz_image.getWidth()-yzSrcRect.width;
			} else {
				yzSrcRect.y += dy;
				if (yzSrcRect.y<0)
					yzSrcRect.y = 0;
				if (yzSrcRect.y>yz_image.getHeight()-yzSrcRect.height)
					yzSrcRect.y = yz_image.getHeight()-yzSrcRect.height;
			}
			yzic.repaint();
			int dx = srcRect.x - startingSrcRect.x;
			ImageCanvas xzic = xz_image.getCanvas();
			Rectangle xzSrcRect =xzic.getSrcRect();
			xzSrcRect.x += dx;
			if (xzSrcRect.x<0)
				xzSrcRect.x = 0;
			if (xzSrcRect.x>xz_image.getWidth()-xzSrcRect.width)
				xzSrcRect.x = xz_image.getWidth()-xzSrcRect.width;
			xzic.repaint();
		}
	}