This issue occurs in Site app and Security app.

Steps to reproduce:

• Open Site app
• Create a folder
• Create a content node inside that folder
• Select that content node, open Move dialog
• Deselect that revealed content node
• Move Before and Move After will be enabled
• Click on any of those buttons
  => Expected: The content node is moved to first level.
  => Actual: It disappears! We can see it using JCR app.

Consider to disable "Move before" and "Move after" in this case like Pages app because this issue doesn't occur in Pages app.

Side note: The issue doesn't come from "move" dialog epic because it even occurs in 5.4.10 which doesn't have "move" dialog enhancements.