From 3ff1139364e952ee406a6e6cfa90fd0623413812 Mon Sep 17 00:00:00 2001
From: Quincy Morgan <quincy.morgan@icloud.com>
Date: Sun, 4 Nov 2018 12:40:59 -0800
Subject: [PATCH] Fixes an error where preventDefault would be called on an
 event object without that function

---
 modules/ui/sidebar.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/modules/ui/sidebar.js b/modules/ui/sidebar.js
index da5028682..721baa37e 100644
--- a/modules/ui/sidebar.js
+++ b/modules/ui/sidebar.js
@@ -197,7 +197,7 @@ export function uiSidebar(context) {
 
         sidebar.toggleCollapse = function(shouldCollapse) {
 
-            if (d3_event) {
+            if (d3_event && typeof d3_event.preventDefault == 'function') {
                 d3_event.preventDefault();
             }