--- a/browser/base/content/browser.xhtml
+++ b/browser/base/content/browser.xhtml
@@ -159,18 +159,14 @@
   <html:template id="customizationPanel">
     <box id="customization-container" flex="1" hidden="true"><![CDATA[
 #include ../../components/customizableui/content/customizeMode.inc.xhtml
     ]]></box>
   </html:template>
 
 #include fullscreen-and-pointerlock.inc.xhtml
 
-  <vbox id="browser-bottombox" layer="true">
-    <!-- gNotificationBox will be added here lazily. -->
-  </vbox>
-
   <html:div id="a11y-announcement" role="alert"/>
 
   <!-- Put it at the very end to make sure it's not covered by anything. -->
   <html:div id="fullscr-toggler" hidden="hidden"/>
 </html:body>
 </html>

--- a/browser/themes/linux/browser.css
+++ b/browser/themes/linux/browser.css
@@ -63,21 +63,16 @@
 }
 
 #nav-bar:not([tabs-hidden="true"]) {
   box-shadow: 0 calc(-1 * var(--tabs-navbar-shadow-size)) 0 var(--lwt-tabs-border-color, rgba(0,0,0,.3));
   /* This is needed for some toolbar button animations. Gross :( */
   position: relative;
 }
 
-#browser-bottombox {
-  /* opaque for layers optimization */
-  background-color: -moz-Dialog;
-}
-
 /* Bookmark menus */
 menu.bookmark-item,
 menuitem.bookmark-item {
   min-width: 0;
   max-width: 32em;
 }
 
 .bookmark-item:not(.subviewbutton) > .menu-iconic-left {

--- a/browser/themes/windows/browser.css
+++ b/browser/themes/windows/browser.css
@@ -167,20 +167,16 @@
   }
 }
 
 #print-preview-toolbar:not(:-moz-lwtheme) {
   appearance: auto;
   -moz-default-appearance: toolbox;
 }
 
-#browser-bottombox:not(:-moz-lwtheme) {
-  background-color: -moz-dialog;
-}
-
 /* Titlebar */
 
 :root[tabsintitlebar][sizemode="normal"] #titlebar {
   appearance: auto;
   -moz-default-appearance: -moz-window-titlebar;
 }
 
 :root[tabsintitlebar][sizemode="maximized"] #titlebar {