corrected SpyPropertyDescriptorComparator

src/fr/ill/ics/nscclient/servant/SpyPropertyDescriptorComparator.java

@@ -30,6 +30,18 @@ public class SpyPropertyDescriptorComparator implements Comparator<SpyPropertyDe
 		if (d1.getSetpointID() == d2.getSetpointID()) {
 			return Integer.compare(d1.getActualID(), d2.getActualID());
 		}
+		
+		if (d2.getSetpointID() == 0) {
+			// d1.setpointID > 0
+			// so d1 is considered smaller than d2
+			return -1;
+		}
+		
+		if (d1.getSetpointID() == 0) {
+			// d2.setpointID > 0
+			// so d1 is considered greater than d2
+			return 1;
+		}
 				
 		return Integer.compare(d1.getSetpointID(), d2.getSetpointID());
 	}