--- a/toolkit/content/widgets/autocomplete.xml
+++ b/toolkit/content/widgets/autocomplete.xml
@@ -1511,16 +1511,19 @@ extends="chrome://global/content/binding
         </xul:description>
       </xul:hbox>
     </content>
     <implementation>
       <constructor><![CDATA[
         let learnMoreLink = document.getElementById("learnMoreLink");
         learnMoreLink.setAttribute("value", this._stringBundle.GetStringFromName("insecureFieldWarningLearnMore"));
         learnMoreLink.setAttribute("href", Services.urlFormatter.formatURLPref("app.support.baseURL") + "insecure-form-field-warning");
+
+        // Unlike other autocomplete items, the height of the insecure warning increases by wrapping.
+        this._handleOverflow();
       ]]></constructor>
 
       <property name="_stringBundle">
         <getter><![CDATA[
           if (!this.__stringBundle) {
             this.__stringBundle = Services.strings.createBundle("chrome://passwordmgr/locale/passwordmgr.properties");
           }
           return this.__stringBundle;