Index: trunk/psphot/src/psphotImageMedian.c
===================================================================
--- trunk/psphot/src/psphotImageMedian.c	(revision 15078)
+++ trunk/psphot/src/psphotImageMedian.c	(revision 15118)
@@ -201,4 +201,26 @@
 	    psVector *sample = NULL;
 
+	    // turn on stats tracing in desired cells
+	    # if (1)
+	    psMetadata *plots = psMetadataLookupPtr (&status, recipe, "DIAGNOSTIC.PLOTS");
+	    assert (plots);
+	    
+	    int xPlot = psMetadataLookupS32 (&status, plots, "IMAGE.BACKGROUND.CELL.HISTOGRAM.X");
+	    assert (status);
+	    int yPlot = psMetadataLookupS32 (&status, plots, "IMAGE.BACKGROUND.CELL.HISTOGRAM.Y");
+	    assert (status);
+
+	    bool gotX = (xPlot < 0) || (xPlot == ix);
+	    bool gotY = (yPlot < 0) || (yPlot == iy);
+
+	    if (gotX && gotY) {
+		psTraceSetLevel ("psLib.math.vectorFittedStats_v4", 6);
+		psTraceSetLevel ("psLib.math.vectorRobustStats", 6);
+	    } else {
+		psTraceSetLevel ("psLib.math.vectorFittedStats_v4", 0);
+		psTraceSetLevel ("psLib.math.vectorRobustStats", 0);
+	    }	    
+	    # endif
+
             if (psImageBackground(stats, &sample, subset, submask, maskVal, rng)) {
                 if (stats->options & PS_STAT_ROBUST_QUARTILE) {