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variable: $minstatcolscale -- color bar min
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default: [autoscale]

Entry to the left of "bar" (above "fthresh:")
controls overlay statistic value for the bottom
of the vertical scale bar (lower right, in the
surface display window).

This also controls the min vertical limit of the
rectangular phase color inset (x-axis is phase,
y-axis is significance), available on clicking
the upper right "rect" button (just to left of
"cm").

Initially autoscaled but can be manually reset.
To redo autoscale, set both max and min to 0.
