1 files changed, 4 insertions, 0 deletions
diff --git a/src/client/model/graph.js b/src/client/model/graph.js
index 9d178636..26bf96b2 100644
--- a/src/client/model/graph.js
+++ b/src/client/model/graph.js
@@ -148,6 +148,10 @@ function Graph() {
 
     this.removeNode = function(id) {
         var n = find_node__by_id(id);
+        if (n === undefined) {
+            console.log('bug: nonexistent node cannot be removed: ' + id);
+            return;
+        }
         this._remove_node_set([n]);
     }