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variable: $maxstatcolscale -- color bar max
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default: [autoscale]

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

This also controls the max 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.
