1 files changed, 1 insertions, 0 deletions
diff --git a/js/Misc/CBLOCK4.js b/js/Misc/CBLOCK4.js
index 0172f4e3..247ef9b2 100644
--- a/js/Misc/CBLOCK4.js
+++ b/js/Misc/CBLOCK4.js
@@ -90,6 +90,7 @@ function CBLOCK4() {
             if ([[this.ci],[this.co]]!=[]) {
                 if (max([[this.ci],[this.co]])>1) {
                     message("vector event links not supported");
+                    throw "user error";
                     var ok = false;
                 }
             }