I am using QGIS 2.18.16 and most of the time I have successfully been using the reshape tool to change the shape of polygons. I have snapping and tracing enabled.
Occasionally when I right-click to finish the reshaping I receive an error 'unknown exception', after which there is no way to undo, reset or start again the tracing. I think the exception is caused because of geometry errors in the polygon that I am reshaping to.
But then I get stuck in reshaping mode. If I close the dialogue window by clicking OK, I am back in the main window and my original reshape trace still exists and I can not find a way to reset it, fix the error, and start again?
All I can do is save the layer, and the project, close down, and reopen QGIS and start again.
Is there an easier and quicker way?