Blender weight can only painted on face Blender 2.8's weight painting behavior is really different than 2.79 and it's bugging me for few month

One of the biggest problem is I can't paint vertex weight by clicking empty space. For example, If I click that area in picture below, it won't paint vertex weight on the mesh.



However, If I paint on the mesh, I can paint vertex weight on the mesh. 



Blender Weight Painting wasn't like this in 2.79. I could paint vertex weight without clicking mesh in 2.79. I couldn't find option to disable this in 2.8. 

Can anyone can guide me to turn off mesh-only vertex painting in 2.8?
You have to set the falloff type from sphere to projected.