IIn Technical, Artistic, and Pencil mode, the contextual selection does not display the correct region.
For example in Tranparency mode :
And in Technical, Artistic or Pencil mode :
jmv
yes that works 
in addition to that, there is a preview for edges and faces but not for vertices.
Now may be a good time to add it.
jmv.
@jmv can you please post a video of what you mean? Is vertex preview missing in only some display modes, or all of them?
When we click with Shift + Ctrl (sub-object selection) in any display mode :
Hi - I see that here and filed RH-57440.
Note that is is only the case for extrusion vertices and not for polysurface, SubD, or mesh vertices.
-wim