--- a/mail/components/addrbook/test/browser/browser_mailing_lists.js
+++ b/mail/components/addrbook/test/browser/browser_mailing_lists.js
@@ -448,16 +448,17 @@ add_task(async () => {
   let deletePromise = TestUtils.topicObserved("addrbook-directory-deleted");
 
   Assert.equal(
     global.booksList.getRowAtIndex(2).querySelector("span").textContent,
     inputs.abName,
     `address book ("${inputs.abName}") is displayed in the address book list`
   );
 
+  global.booksList.focus();
   global.booksList.selectedIndex = 2;
   EventUtils.sendKey("DELETE", global.abWindow);
 
   await Promise.all([mailingListWindowPromise, deletePromise]);
 
   let addressBook = MailServices.ab.directories.find(
     directory => directory.dirName == inputs.abName
   );