Hi Ron,
This sounds strange, never seen this before. Not sure what you mean by "going into ArcMap without our custom code", though. Anyways, you should check if the Flip command is available in ArcMap. This can be done in several ways (try running whichever you'll find):
- in ArcToolbox, under the Editing Tools;
or
- Customize menu > Customize mode > Commands tab > Show commands containing - type in Flip > you'll find Flip under the Editor in the Categories list > drag and drop Flip command on some toolbar you have in ArcMap (for instance, Editor toolbar).
Sorry for asking again, just want to make sure that we are on track. You entered the editing mode (Editor > Start Editing) > used the Edit Tool by clicking its icon on the Editor toolbar, double-clicked the line feature > the line turned out green and a start and end vertices appeared. Now you right-click the line feature while having the mouse cursor either on a vertex or the edge, but don't get a context menu you need.
Out of curiousity, what type of context menu you get when you right-click the selected line feature in the editing mode? Do you get any?