-------------------------------------------
variable: $normdfracflag -- frac vs. mm
-------------------------------------------
default: 1

"NormSamp, Clust Controls" parameter.  To adjust,
access pop-up by L-click on "label:" (bold).

This flag affects the operation of the following
functions:

  write_label_timecourses_stats
  ("label:" line "T" and "S" buttons)

  paint_surface
  ("val3d:" line "PAINT" button)

  find_orig_vertex_coordinates
  (upper right SEND button)

  write_val_visible_vertices
  (left-clk "W" button on "label:" line)

If not ticked, search limits in first pair of
entries are used (in mm).

If ticked, search limits in next pair of entries
are used, and are entered as 0-1 fractions of the
distance between the sample surface and the pial
surface.

The white-matter-to-pial surface distance can
either come from the MGH freesurfer thickness
file ($samevtxthickflag = 0), or from the
distance to the equivalently numbered pial
surface vertex ($samevtxthickflag = 1).

