--- a/devtools/client/netmonitor/test/browser_net_filter-autocomplete.js
+++ b/devtools/client/netmonitor/test/browser_net_filter-autocomplete.js
@@ -46,17 +46,17 @@ add_task(async function() {
   // Let the requests load completely before the autocomplete tests begin
   // as autocomplete values also rely on the network requests.
   const waitNetwork = waitForNetworkEvents(monitor, REQUESTS.length);
   loadFrameScriptUtils();
   await performRequestsInContent(REQUESTS);
   await waitNetwork;
 
   EventUtils.synthesizeMouseAtCenter(
-    document.querySelector(".devtools-filterinput"), {}, window);
+    document.querySelector(".devtools-filterinput"), {}, document.defaultView);
   // Empty Mouse click should keep autocomplete hidden
   ok(!document.querySelector(".devtools-autocomplete-popup"),
     "Autocomplete Popup still hidden");
 
   document.querySelector(".devtools-filterinput").focus();
   // Typing a char should invoke a autocomplete
   EventUtils.sendString("s");
   ok(document.querySelector(".devtools-autocomplete-popup"),