Triangles Index always zero - Custom Editor

In short, i have a custom editor script. I am trying to get the triangle index by clicking on a triangle. However, no matter what triangle on click on, the triangle index is always zero. The hit point does change as expected. Here is the portion of code i am using for the raycast which is contained within OnSceneGUI().

var ray = HandleUtility.GUIPointToWorldRay(e.mousePosition);
var hit = new RaycastHit();

if (Physics.Raycast(ray, out hit))
{
    Debug.Log("Triange Index: " + (hit.triangleIndex * 3) + " Hit Point: " + hit.point);
}

From the Unity Scripting Reference:

Triangle index is only valid if the collider that was hit is a MeshCollider.

Just use a mesh collider instead.