Mode menu keeps reverting to Edit Strokes

Blender V2.79. After using GreasePencil Draw and Erase I cannot get the Mode menu to revert to default.
It keeps going back to only Object and Edit Strokes. No web answers have worked and I am out of ideas.
Here is the file AftHatchCoamings.blend (1.8 MB)

and if anyone can tell me what I have done wrong I will be very grateful.
Thanks

Edit: No idea why but it has started working again. Good in one way but a worry when you have no idea what caused it and how to avoid same happening again in the future.

I was unable to reproduce the problem, but I did notice that there were three hull objects sitting right on top of each other (triple geometry) I am guessing that you were selecting one of those other copies that was in a different mode.