1 files changed, 6 insertions, 1 deletions
diff --git a/index.html b/index.html
index 554ff15..b8726c3 100644
--- a/index.html
+++ b/index.html
@@ -790,7 +790,12 @@
                   {
                     var stylesheet = graph.getStylesheet();
                     var style = stylesheet.styles[cell.value.getAttribute('style')];
-                    var displayedLabel = style['displayedLabel'];
+                    var displayedLabel = null;
+
+                    if(style != null) {
+                      displayedLabel = style['displayedLabel'];
+                    }
+                    
                     if(displayedLabel != null) {
                       var displayParameter = cell.blockInstance.instance.displayParameter;
                       for(i in displayParameter) {