On selecting a folder in the project view, you can't search contents of other folders, even on unselecting it later.

Steps to Reproduce:
1. Create a new project.
2. Create some new folders in the Assets List.
3. Add some assets to the folders that can be searched. (nested folders can also be created)
4. Select any folder.
5. Try searching contents of other folders.(apart from selected folder)
6. Observe the issue. Nothing will be displayed in the project view search.

Notes:
- Check the attached video to reproduce the issue.
- Happen Always.
- Appears on both OSX and Windows.

Occurring On: 2018.2.0a6, 2018.2.0a8

Working Fine On: 2018.2.0a5, 2018.1.0f1