Sprite Atlas "Object for Packing", select object window displays editor UI icons

Steps to Repro:
1. Open attached project > assets
2. Select new sprite atlas > click '+' icon in objects in packing
3. See select object window

Actual Result:
All editor's hidden icons and folder are listed n the list

Expected Result:
Only default sprite icons and sprites present in assets folder should list

Occurring With:
2018.2.0a7, 2018.2.0a6

Working With:
2018.2.0a5, 2018.2.0a4, 2018.2.0a2

Environment:
Windows 10, Mac 10.12, 10.13