diff --git a/app/src/main/java/org/ntlab/acanthus_client/entities/Position.java b/app/src/main/java/org/ntlab/acanthus_client/entities/Position.java
index c194913..f311050 100644
--- a/app/src/main/java/org/ntlab/acanthus_client/entities/Position.java
+++ b/app/src/main/java/org/ntlab/acanthus_client/entities/Position.java
@@ -33,6 +33,13 @@
     //
     @Override
     public int compareTo(Object o) {
+        if (o instanceof Position) {
+            if (i < ((Position) o).i) {
+                return -1;
+            } else if (i > ((Position) o).i) {
+                return 1;
+            }
+        }
         return 0;
     }
 }