Scenario 1 repordering in-memory scene

Steps to reproduce:

1. Add a new in-memory scene by right click an existing scene header
2. Try to reorder this in-memory scene 

Actual results: in-memory scene barely moves

Expected results: user should be able to move/reorder in-memory scenes

Scenario 2 repordering scenes when searched/filtered

Steps to reproduce:

1. Load multiple scenes in hiearchy
2. search for a common letter to allow all scenes appear
3. reorder scenes

Actual results: scene fail to move and appear undraggable

Expected results: user should be able to move/reorder  scenes

Reproducible with versions: 6.3 and up

Not reproducible with versions: 

Can’t test with versions: 

Tested on (OS): mac

Notes: