--- a/browser/components/customizableui/content/customizeMode.inc.xul
+++ b/browser/components/customizableui/content/customizeMode.inc.xul
@@ -28,16 +28,18 @@
 #endif
       <button id="customization-toolbar-visibility-button" label="&customizeMode.toolbars;" class="customizationmode-button" type="menu">
         <menupopup id="customization-toolbar-menu" onpopupshowing="onViewToolbarsPopupShowing(event)"/>
       </button>
       <button id="customization-lwtheme-button" label="&customizeMode.lwthemes;" class="customizationmode-button" type="menu">
         <panel type="arrow" id="customization-lwtheme-menu"
                onpopupshowing="gCustomizeMode.onLWThemesMenuShowing(event);"
                onpopuphidden="gCustomizeMode.onLWThemesMenuHidden(event);"
+               position="topcenter bottomleft"
+               flip="none"
                role="menu">
           <label id="customization-lwtheme-menu-header" value="&customizeMode.lwthemes.myThemes;"/>
           <label id="customization-lwtheme-menu-recommended" value="&customizeMode.lwthemes.recommended;"/>
           <hbox id="customization-lwtheme-menu-footer">
             <toolbarbutton class="customization-lwtheme-menu-footeritem"
                            label="&customizeMode.lwthemes.menuManage;"
                            accesskey="&customizeMode.lwthemes.menuManage.accessKey;"
                            tabindex="0"