Motion Design OUTLINER

The ability to hide and lock items in the new motion design outliner is fantastic.
I’m having an issue of when I save and close a project and reopen it, everything hidden is visible again. Can anyone tell me why?
Thanks in advance

I assume you are referring to the editor visibility (and not the runtime one - hidden in game flag).
Both of these data live in the actor, but the flag that drives the editor visibility is transient (i.e. does not save),
and instead the Actor has a hide in editor at startup flag which does save and is the flag used to set the transient editor visibility.
If you want these to persist across editor sessions you could look to right clicking the actor in the viewport > visibility and manipulating it from there.
I don’t fully recommend it though as it’s a bit hard to find and once you set it it’ll always hide when you load up your level in the editor even if you had toggled to show it after… and the only solution is to go through this right click again and selecting “show selected at startup”