Index: /trunk/ippTools/src/difftoolConfig.c
===================================================================
--- /trunk/ippTools/src/difftoolConfig.c	(revision 18677)
+++ /trunk/ippTools/src/difftoolConfig.c	(revision 18678)
@@ -131,5 +131,5 @@
     psMetadataAddStr(definebyqueryArgs, PS_LIST_TAIL, "-tess_id", 0, "search by tess ID", NULL);
     psMetadataAddStr(definebyqueryArgs, PS_LIST_TAIL, "-filter", 0, "search by filter", NULL);
-    psMetadataAddF32(definebyqueryArgs, PS_LIST_TAIL, "-good_frac", 0, "minimum good fraction of skycell", NULL);
+    psMetadataAddF32(definebyqueryArgs, PS_LIST_TAIL, "-good_frac", 0, "minimum good fraction of skycell", NAN);
     psMetadataAddStr(definebyqueryArgs, PS_LIST_TAIL, "-kind", 0, "search by kind", NULL);
     psMetadataAddStr(definebyqueryArgs, PS_LIST_TAIL, "-workdir", 0, "define workdir (required)", NULL);