title: Selected vertex did not highlight in Blender 3D
body: <p>I've made a Cube in Blender.
  Using Python I did enter EDIT mode and selected one vertex:</p>
  
  <pre><code>import bpy
  
  bpy.ops.mesh.primitive_cube_add()
  bpy.ops.object.mode_set(mode="EDIT")
  bpy.ops.mesh.select_all(action="DESELECT")
  bpy.context.tool_settings.mesh_select_mode = (True , False , False)
  bpy.context.object.data.vertices[0].select = True
  
  bpy.context.object.data.vertices[0].co = (-3,-2,-3)
  </code></pre>
  
  <p>However, the vertex was not highlighted in orange,
  and although I told the vertex to go to -3,-2-,-3 
  it's position did not update.</p>
  
  <p>Why did it not highlight nor move ?</p>