Changed sequence timeline to match attachment timeline behavior.
Is this what I think it is? 
Please explain
Explain changelog item from 4.2.38
warmanw This is a fix related to the following thread, so please see Nate's explanation in the following thread for more details:
https://esotericsoftware.com/forum/d/27265-it-seems-that-attachment-mixing-is-not-working-properly-in-this-version-42/4