Editor on Mac can display progress bars on top of other application windows when the Editor is in the background

The Editor on Mac will display progress bars on top of other application windows when the Editor is in the background and does not currently have focus. This can interfere when attempting to do other work while waiting for the Editor to complete a task.

REGRESSION:
No.

1. Have one or more applications already open in addition to the Editor, such as Xcode.
2. Create a new Blank Blueprint project with starter content.
3. Add a new empty folder in the root project Content folder.
4. Drag the "Props" folder from Starter Content to the new folder created in the previous step.
5. Select the "Move Here" option.
6. Once the move process begins, bring another application window into focus on top of the Editor (eg. use ⌘Tab to switch to another application).

RESULT:
During the move process, the Editor will display progress bars on top of the application window that currently has focus.

EXPECTED:
The progress bars will be displayed on top of the Editor window, but behind any other application window that currently has focus.