Steps to reproduce:
1. Open the attached project "Case_1141454"
2. Navigate to Project -> Assets -> Scenes and open "TexturePack" scene
3. In the Hierarchy window Select the Child of Canvas "TexturePack"
4. In the Inspector window Click on Browser
5. Select "Emoji_Apple" folder and click "Select Folder"
6. In the Inspector Window click "Create Sprite Assets"
-- Notice the console error "NullReferenceException: Object reference not set to an instance of an object"

Expected Results: Sprite Assets move to a different folder after it is created
Actual Results: Sprite Assets are prevented from moving to a different folder by an error

Reproducible with: 2018.3.14f1, 2019.1.0f2, 2019.2.0a14, 2019.3.0a1

Notes: Clicking on the error will point to Inspector window Asset. Versions lower than 2018.3.0a10 do not support this custom editor