Only handle click actions for left & middle buttons

ui/webui/resources/js/util.js

Index: ui/webui/resources/js/util.js
diff --git a/ui/webui/resources/js/util.js b/ui/webui/resources/js/util.js
index d2820815f74dd5763ef91bc2e16dce96622fd74c..37bc2bf327b00d0f0fcf41715bf23390ccefe370 100644
--- a/ui/webui/resources/js/util.js
+++ b/ui/webui/resources/js/util.js
@@ -214,6 +214,8 @@ function queryRequiredElement(selectors, opt_context) {
 // call into the browser to do the navigation.
 ['click', 'auxclick'].forEach(function(eventName) {
   document.addEventListener(eventName, function(e) {
+    if (e.button > 1)
+      return; // Ignore buttons other than left and middle.
     if (e.defaultPrevented)
       return;