To construct an open line , select the open line tool,
either by clicking on the open line button or by selecting
Tools->Open Line (Ctrl-L).
To construct a closed line , select the closed line tool,
either by clicking on the closed line button or by selecting
Tools->Closed Line (Ctrl+Shift-L).
Use the left mouse button to click on each vertex defining the path.
To complete the path, do one of the following:
Double-click instead of single-clicking on the final vertex:
this performs the combined function of defining the vertex and
finishing the path. If you use this method, be careful not to
accidentally create two coincident vertices at the end point, or
it will cause a problem for any mid or end
|| that you apply.
Single-click on the final vertex and then
complete the path by pressing the Enter key or by
clicking on the finish button or by selecting
Tools->Finish.
If you have used the closed line tool, the path will automatically
be closed by inserting a line between the end vertex
and the initial vertex.