I am using ArcGIS 10.3 for Desktop.
I followed the instructions provided in the Help menu i.e. edit, select feature, edit vertices, and then used the continue feature tool to extend the line.
Why is the continue feature tool greyed out?
The asker found that they:
can extend a line (eg road) to any end point (not necessarily another feature-could be just a 'dead end') as follows:
- edit/start editing
- select layer (feature class) to edit eg roads/OK/select road feature/select line construction tool
- select on end point/digitise new road extension/ double click to finish
- select both original road and new road extension (hold shift key to select both)
- editor/merge/save edits.