$#Edit > Merge Polyline
1.Select Edit > Merge Polyline to enter "edit" mode.
2.Use the mouse to select each individual line segment that you wish to merge.
3.Select Edit > Merge Polyline again or press [ESC] to get out of "edit" mode.
The selected lines are now merged into one polyline.
Note
You cannot merge lines or polylines from different layers into one polyline.