Getting an error in 2015 when trimming lines with a 3d polyline. (see attached drawing).

Download 0011 – trimming 3d polylines 2015_test1

I select the complex 3d polyline as the trimming line, then when I go to trim the lines. IF I accidentally hover over the 3d polyline I am using to trim it just freezes for up to 5 minutes.

If I turn off live preview I don’t get the error?

The more complex the 3d polyline the longer the wait!

What’s wrong?