Here is a meshtrim bug for you. Use the curves to meshtrim in top view.
2016-09-26 meshtrimbug.3dm (1.2 MB)
Hi Jorgen - thanks, I see that. If you Extend the curve to the right until it goes past the edge of the mesh it seems to complete the trim correctly. (or include the little line at the end of the curve as a trimming object)
https://mcneel.myjetbrains.com/youtrack/issue/RH-35746
-Pascal