--- a/browser/components/downloads/test/browser/browser_downloads_panel_footer.js
+++ b/browser/components/downloads/test/browser/browser_downloads_panel_footer.js
@@ -6,16 +6,17 @@ function *task_openDownloadsSubPanel() {
 
   let downloadsDropmarker = document.getElementById("downloadsFooterDropmarker");
   EventUtils.synthesizeMouseAtCenter(downloadsDropmarker, {}, window);
 
   yield popupShownPromise;
 }
 
 add_task(function* test_openDownloadsFolder() {
+  yield SpecialPowers.pushPrefEnv({"set": [["browser.download.showPanelDropmarker", true]]});
   yield task_openPanel();
 
   yield task_openDownloadsSubPanel();
 
   yield new Promise(resolve => {
     sinon.stub(DownloadsCommon, "showDirectory", file => {
       resolve(Downloads.getPreferredDownloadsDirectory().then(downloadsPath => {
         is(file.path, downloadsPath, "Check the download folder path.");