Landscape brush not visible when landscape material uses World Position Offset

Landscape brush not visible when landscape material uses World Position Offset.

Update: Brush also not visible when landscape material uses displacement. Tested in Binary 4.10.2 from launcher.

1. Create a simple landscape material (See image)
2. Create a simple landscape
3. Apply the material to the landscape
4. Paint the landscape with the layer assigned to the World Position Offset (In the example image its the Green Layer)
5. Move brush over the painted landscape from above

Result: Brush is not visible over top of the World Position Offset landscape