Index: trunk/ppStack/src/ppStackMatch.c
===================================================================
--- trunk/ppStack/src/ppStackMatch.c	(revision 20753)
+++ trunk/ppStack/src/ppStackMatch.c	(revision 20754)
@@ -82,5 +82,9 @@
         coords->data.F32[0] = source->peak->xf;
         coords->data.F32[1] = source->peak->yf;
-        if (psTreeWithin(tree, coords, exclusion) == 1) {
+
+        long numWithin = psTreeWithin(tree, coords, exclusion); // Number within exclusion zone
+        psTrace("ppStack", 5, "Source at %.0f,%.0f has %ld sources in exclusion zone",
+                coords->data.F32[0], coords->data.F32[1], numWithin);
+        if (numWithin == 1) {
             // Only itself inside the exclusion zone
             filtered = psArrayAdd(filtered, filtered->n, source);