I wish there was a good way to end melodies. I think others have mentioned this; it’s a real pain having other bars added after trying to finish on a resolving note: no drums, no bass; everything just stopping at once! 
Yes, the issue of auto-adding bars has been around for a while now. We need to fix this, I agree.
But I think from a musical perspective there is a far better way than just stopping everything at once at the last 16th note of a bar. In the “real” world, most of the time musicians won’t do this but play a long or short note on beat 1 of the last bar instead.
To simulate this, you can create a band change marker on your last bar and then use break or sustain patches for all harmony, bass and drum instruments. This prevents the drums from playing on all the extra empty bars at the end and sounds far more natural. Here is an example of what a band for the last bar could look like:
Thanks Dennis; it worked a treat!