Export is not same as preview render

[shotcut]

Closing due to duplicate at

Text filter is removing spaces when exported

This is a follow-on to my previous message “Export is not same as preview render”. Shotcut plays video tracks with various filters exactly as I would expect. But when I export the project and play back the exported version of the video track(s) with VLC, it’s really just the original input video all over again–NO compositing or filtering whatsoever! What in the world am I missing? Is there something I’m supposed to do just before exporting? I am stumped–please help! Harvey