Media Player not "remembering" Media Source


I’m having a big issue with the Media Player.

It is vital to my project that I play several videos inside a level.

I’ve certainly done this a dozen times, but now I’ve run into a problem:

When I open the Media Player and double-click on my Media Source ( a h.264 MP4 Video), it works perfectly - I can see the preview in the Media Player Window, and it also plays on the actor in my level.

However, as soon as I close the Media Player and reopen it, it’s… lost.

The “Media Source” tab is simply empty.

I’ve tried this now with six files in all ways and combinations, but the result is the same:

As soon as I close a Media Player, the Media Source is being erased.

What’s going on here?

Can anyone help?

Many thanks in Advance.

Here’s a “before” (bottom) and “after” (top) closing the media player. As you can see, the Media Source is gone.