Thank you for reporting this. We could look into the issue and submitted a fix that will be included in a future release.
The issue shows when one adds a Fixture Patch to a DMX Library Track that has more than one section to it.
Until the fix is released, there’s several options to work around the issue:
- Remove any additional section from the DMX Library Track, so that there is only one single DMX Library section in your track and add the patches there.
- Add a new DMX Library track and add the patches to the new track instead of your existing one.
- Build 5.6 from source and merge in the fix change https://github.com/EpicGames/UnrealEngine/commit/1956b0cea7ea9625c6e501652371819a9e6f9716
Either will allow you to add patches to the DMX Library Section again.