C++ Classes subfolders cannot be viewed in CB if Sources Panel is closed

When a new class is added to a subfolder, by entering the folder name in the Add C++ Class - Path field, navigating to the new subfolder doesn't work if the Content Brower's Sources Panel is closed

Workaround:
Opening / expanding Sources panel allows the editor to navigate into the newly created folder

Regression:
No - same behavior occurs in 4.16.3 (CL 3561208)

1. Open UE4 Editor (any project)
2. Ensure Content Browser sources panel is hidden/closed by clicking "Show or hide sources panel" icon below Add New
3. Right click in CB to add new code class
4. Select Actor and click next
5. Add a subfolder named "Test" by typing Test at the end of the Path field and click create
6. After the editor finishes loading, click the folder icon next to Content in CB and select C++ Classes
7. Navigate into Classes folder until you reach Test folder
8. Double click on Test folder

Result:
The folder does not open to show newly added class

Expected:
Double clicking on the folder opens it, showing any files inside

Cannot view C++ subdirectories with Sources Panel Hidden in Content Brow