Extending paths
Existing open paths can be extended with the Bezier Pen tool or the Freehand Drawing tool. Select the path you wish to extend and switch to either the Bezier Pen tool or the Freehand Drawing tool. The selected path will show handles on its endpoints only.
Use the tool as you would normally to create a path, but start on either of the endpoint handles. The visual feedback will immediately show that you are extending the existing path, and a path closing target will show where you would need to end the path in order to close it. As with normal tool operation, you can also end the path by releasing the mouse button anywhere (with the Freehand Drawing tool) or by double-clicking (with the Bezier Pen tool) to leave the path open.
This feature is useful if you want to take a rest during a long edge tracing, or if you want to start the path with one tool but finish it with the other.
If you want to extend a closed path, you must first open it, which can be done with the Reshaping tool .