diff --git a/.eslintrc.js b/.eslintrc.js
index 829deee..510cba8 100644
--- a/.eslintrc.js
+++ b/.eslintrc.js
@@ -50,6 +50,9 @@ module.exports = {
         global: true,
         Services: true,
       },
+      rules: {
+        "mozilla/reject-importGlobalProperties": "off"
+      }
     }
   ]
 };
diff --git a/calendar/experiments/calendar/parent/ext-calendarItemDetails.js b/calendar/experiments/calendar/parent/ext-calendarItemDetails.js
index e2a1e05..d0d6fad 100644
--- a/calendar/experiments/calendar/parent/ext-calendarItemDetails.js
+++ b/calendar/experiments/calendar/parent/ext-calendarItemDetails.js
@@ -8,6 +8,8 @@ var { ExtensionUtils: { ExtensionError } } = ChromeUtils.importESModule("resourc
 
 var { ExtensionSupport } = ChromeUtils.importESModule("resource:///modules/ExtensionSupport.sys.mjs");
 
+Cu.importGlobalProperties(["URL"]);
+
 this.calendarItemDetails = class extends ExtensionAPI {
   onLoadCalendarItemPanel(window, origLoadCalendarItemPanel, iframeId, url) {
     const { setupE10sBrowser } = ChromeUtils.importESModule("resource://tb-experiments-calendar/experiments/calendar/ext-calendar-utils.sys.mjs");