Use this tool to make curved lines.

Click the left mouse button on the tool, then at the starting point of your line. Move the mouse and see the line element 'rubber-band'. While you are drawing, the end of each element is marked by a blue blob.

To end the line element and add a new one to the line, click the left mouse button once, then move the mouse again.

You can continue to add as many elements as you need.

To end the line, double-click the left mouse button or click once then press Return.

As you make the line, you will notice green 'control points' between the blue blobs. For more about these, see the editing section.