diff --git a/browser/components/customizableui/src/CustomizeMode.jsm b/browser/components/customizableui/src/CustomizeMode.jsm
index ac55bd99b1f..fe90b40ebe6 100644
--- a/browser/components/customizableui/src/CustomizeMode.jsm
+++ b/browser/components/customizableui/src/CustomizeMode.jsm
@@ -633,9 +633,6 @@ CustomizeMode.prototype = {
 
     if (aNode.hasAttribute("flex")) {
       wrapper.setAttribute("flex", aNode.getAttribute("flex"));
-      if (aPlace == "palette") {
-        aNode.removeAttribute("flex");
-      }
     }
 
 
@@ -702,10 +699,6 @@ CustomizeMode.prototype = {
       toolbarItem.checked = true;
     }
 
-    if (aWrapper.hasAttribute("flex") && !toolbarItem.hasAttribute("flex")) {
-      toolbarItem.setAttribute("flex", aWrapper.getAttribute("flex"));
-    }
-
     if (aWrapper.hasAttribute("itemcommand")) {
       let commandID = aWrapper.getAttribute("itemcommand");
       toolbarItem.setAttribute("command", commandID);
diff --git a/browser/themes/shared/customizableui/customizeMode.inc.css b/browser/themes/shared/customizableui/customizeMode.inc.css
index 61d6282c18c..82dc9018441 100644
--- a/browser/themes/shared/customizableui/customizeMode.inc.css
+++ b/browser/themes/shared/customizableui/customizeMode.inc.css
@@ -137,6 +137,10 @@ toolbarpaletteitem[place="toolbar"] {
   display: none;
 }
 
+#wrapper-personal-bookmarks:not([place="toolbar"]) > #personal-bookmarks {
+  -moz-box-pack: center;
+}
+
 #customization-palette > toolbarpaletteitem > label {
   text-align: center;
   margin-left: 0;
diff --git a/browser/themes/shared/customizableui/panelUIOverlay.inc.css b/browser/themes/shared/customizableui/panelUIOverlay.inc.css
index 2f22280cb75..058ddf40658 100644
--- a/browser/themes/shared/customizableui/panelUIOverlay.inc.css
+++ b/browser/themes/shared/customizableui/panelUIOverlay.inc.css
@@ -212,6 +212,8 @@ toolbaritem[cui-areatype="menu-panel"][sdkstylewidget="true"]:not(.panel-wide-it
 .panelUI-grid .toolbarbutton-1 > .toolbarbutton-icon,
 .customization-palette .toolbarbutton-1 > .toolbarbutton-menubutton-button > .toolbarbutton-icon,
 .customization-palette .toolbarbutton-1 > .toolbarbutton-icon,
+.panelUI-grid #bookmarks-toolbar-placeholder > .toolbarbutton-icon,
+.customization-palette #bookmarks-toolbar-placeholder > .toolbarbutton-icon,
 .panel-customization-placeholder-child > .toolbarbutton-icon {
   min-width: 32px;
   min-height: 32px;
@@ -532,8 +534,8 @@ toolbarpaletteitem[place="palette"] > #bookmarks-menu-button > .toolbarbutton-me
 }
 
 toolbarpaletteitem[place="palette"] > #search-container {
-  min-width: calc(@menuPanelWidth@ / 3);
-  width: calc(@menuPanelWidth@ / 3);
+  min-width: 7em;
+  width: 7em;
 }
 
 #edit-controls@inAnyPanel@,