Limit 2D panning north/south

**Currently when the viewer is in 2D panning in north/south direction is limited to being half off the screen for some reason. Why not limit panning to be the edge of the window or disable vertical panning if the entire height fits within the window? What is the point of seeing half the screen as black when the user is in 2D? Also if the window is taller than it is wide the zoom limiting is suddenly disabled and the user can zoom out forever in 2D the same as 3D. Sandcastle => **

That seems like a bug to me. Would you mind opening an issue on GitHub ( if there isn’t one already?