After much testing and SAS Tech Support, the answer is it cant be done.  There appears to be no switch or setting to turn off the unusual way of doing BY processing.   Proc SGPANEL is (in my opinion) incorrectly written, in that it gets information about the WHOLE dataset - across all by groups - to determine the axis scaling.  I'm file with it using the whole PANELBY group to determine the axis scaling, but not the whole dataset.   I have used a hack which makes separate calls to SGPANEL to achieve what I wanted.  SAS Tech Support also show me a way using PROC TEMPLATE and PROC SGRENDER.  Rather mind blowing to get round a deficiency in the SAS code for SGPANEL.     ... View more