Using the arrow keys to navigate the Attach To dropdown causes accidental selection

When using the arrow keys to navigate the Attach To menu, the first actor that is highlighted will automatically be selected instead of allowing the user to select the actor they wish.

Regression?: No
This also occurred in 4.12.5 Release

1. Open or create a project
2. Right-click an actor in the World Outliner (add some if there aren't any there)
3. Using the arrow keys, navigate down to "Attach To" and hit enter (You'll need to click on this in 4.14 most likely, enter will not work)
4. Using the arrow keys, try to navigate downwards to select an actor.
   Result: When you highlight the first actor, it'll automatically be selected and the attaching process will occur
   Expected: No asset should be selected using the arrow keys, it should require hitting enter or clicking the desired asset