Bug 1649295 - fix OSX test failures of comm/calendar/test/browser/timezones/browser_timezones.js. r=darktrojan

calendar/test/modules/ItemEditingHelpers.jsm

@@ -18,6 +18,7 @@ const EXPORTED_SYMBOLS = [
   "setData",
 ];
 
+var { Services } = ChromeUtils.import("resource://gre/modules/Services.jsm");
 var elementslib = ChromeUtils.import("resource://testing-common/mozmill/elementslib.jsm");
 var { sendString, synthesizeKey, synthesizeMouseAtCenter } = ChromeUtils.import(
   "resource://testing-common/mozmill/EventUtils.jsm"
@@ -596,9 +597,11 @@ async function setTimezone(dialogWindow, iframeWindow, timezone) {
     undefined,
     "chrome://calendar/content/calendar-event-dialog-timezone.xhtml",
     async timezoneWindow => {
+      if (Services.focus.activeWindow != timezoneWindow) {
         let focus = BrowserTestUtils.waitForEvent(timezoneWindow, "focus", true);
         timezoneWindow.focus();
         await focus;
+      }
 
       let timezoneDocument = timezoneWindow.document;
       let timezoneMenulist = timezoneDocument.getElementById("timezone-menulist");