You are not seeing the content that you're expecting to see in the Navigation Pane.
This issue can be caused by a corruption of the local cache. There's several methods to refresh the local cache in Remote Desktop Manager for Mac.
Press Command + Shift + R on your keyboard
Hold the Shift button on your keyboard and click on the refresh button in the Quick Access Toolbar.
Data Source Refresh Button
You can manage the local cache by doing a Vaccum, a Repair or a Delete. Please consult Manage Cache topic for more information.