--- a/browser/extensions/formautofill/FormAutofillPreferences.jsm
+++ b/browser/extensions/formautofill/FormAutofillPreferences.jsm
@@ -65,17 +65,16 @@ FormAutofillPreferences.prototype = {
    * Create Form Autofill preference group
    *
    * @param  {XULDocument} document
    */
   createPreferenceGroup(document) {
     let formAutofillGroup;
     let addressAutofill = document.createElementNS(XUL_NS, "hbox");
     let addressAutofillCheckbox = document.createElementNS(XUL_NS, "checkbox");
-    let spacer = document.createElementNS(XUL_NS, "spacer");
     let savedAddressesBtn = document.createElementNS(XUL_NS, "button");
 
     if (this.useOldOrganization) {
       let caption = document.createElementNS(XUL_NS, "caption");
       let captionLabel = document.createElementNS(XUL_NS, "label");
 
       formAutofillGroup = document.createElementNS(XUL_NS, "groupbox");
       formAutofillGroup.hidden = document.location.href != "about:preferences#privacy";
@@ -100,21 +99,20 @@ FormAutofillPreferences.prototype = {
     savedAddressesBtn.setAttribute("label", this.bundle.GetStringFromName("savedAddresses"));
     addressAutofillCheckbox.setAttribute("label", this.bundle.GetStringFromName("enableAddressAutofill"));
 
     // Manually set the checked state
     if (this.isAutofillEnabled) {
       addressAutofillCheckbox.setAttribute("checked", true);
     }
 
-    spacer.flex = 1;
+    addressAutofillCheckbox.flex = 1;
 
     formAutofillGroup.appendChild(addressAutofill);
     addressAutofill.appendChild(addressAutofillCheckbox);
-    addressAutofill.appendChild(spacer);
     addressAutofill.appendChild(savedAddressesBtn);
   },
 
   /**
    * Handle events
    *
    * @param  {DOMEvent} event
    */