SUMMARY I feel like this would greatly improve the performance of editing multiple sequences together especially when there's effects inside them. Ideally the proxies would invalidated and recreated when changes are made, or creating the proxy would lock/freeze the sequence requiring you to manually remove the proxy to edit. STEPS TO REPRODUCE 1. right click a sequence in the Project Bin 2. check the box for "Proxy Clip"
the proxies would also need an alpha channel