USD Stage window doesn't update when selecting other USDStageActors

Toggling between USD Stage Actors does not update the USD Stage window with the information from the selected USD Stage. Only the information from the last loaded USD Stage Actor is present.

Setup

1. You'll need to add "bForceEnableRTTI = true;" to UE4Editor.Target.cs and compile
2. If you do not have any USD files available you can download some here: [Link Removed]

Repro

1. Open the UE4 Editor and create a Blank C++ project
2. A folder containing your code project should open. Go to YourProjectEditor.Target.cs and add "bForceEnableRTTI = true;"
3. Open the UE4 Editor and load your project. Rebuild if prompted
4. Enabled the USD Importer plugin and restart the Editor
5. Open the USD Stage Window (Window>USD Stage) and load one of your USD files (File>Open)
6. Then in the Place Actors pane search for USD Stage Actor and drag one into the Level
7. Set the Root Layer to a different USD file
8. Click between the two while USD Stage is open

Results: Only the latest USD asset gets loaded into USD Stage

Expected: USD Stage should react to the selected UsdStageActor in the scene and reload the information in the window