Cursor over Navigation Mesh

Hi all

I am trying to find a way to determine if the mouse cursor is currently over a valid part of the navigation mesh / area and I always seem to have a result of true from ProjectPointToNavigation.

Using the Top-Down template as a test bed I had tried to implement not being able to click (or show cursor) if the mouse pointer is not over an actual walkable area but I always seem to get “true” from ProjectPointToNavigation regardless of where the mouse pointer is.

Has anyone ever managed to “detect” when the mouse is only over the navigation mesh and ignore if over anything else.

Thanks in advance.