diff --git a/content/treestyletab/treestyletab.css b/content/treestyletab/treestyletab.css
index 242d530c..c8397224 100644
--- a/content/treestyletab/treestyletab.css
+++ b/content/treestyletab/treestyletab.css
@@ -28,7 +28,9 @@ tabbrowser:not([treestyletab-tabbar-autohide="hidden"]) .treestyletab-tabbar-tog
 .tabbrowser-strip[treestyletab-tabbar-fixed="true"]+splitter,
 .tabbrowser-strip[treestyletab-print-preview="true"],
 .tabbrowser-strip[treestyletab-print-preview="true"]+splitter,
-#TabsToolbar[treestyletab-print-preview="true"] {
+#TabsToolbar[treestyletab-print-preview="true"],
+window[chromehidden~="toolbar"] .tabbrowser-strip[treestyletab-tabbar-placeholder="true"],
+window[chromehidden~="toolbar"] .tabbrowser-strip[treestyletab-tabbar-placeholder="true"]+splitter {
 	visibility: collapse;
 }
 
diff --git a/content/treestyletab/treestyletabbrowser.js b/content/treestyletab/treestyletabbrowser.js
index b4ecc2d2..7f38d2c2 100644
--- a/content/treestyletab/treestyletabbrowser.js
+++ b/content/treestyletab/treestyletabbrowser.js
@@ -196,6 +196,7 @@ TreeStyleTabBrowser.prototype = {
 				placeHolder = document.createElement('hbox');
 				placeHolder.setAttribute('anonid', 'strip');
 				placeHolder.setAttribute('class', 'tabbrowser-strip');
+				placeHolder.setAttribute(this.kTABBAR_PLACEHOLDER, true);
 				b.mTabBox.insertBefore(placeHolder, toggler.nextSibling);
 			}
 			if (placeHolder != this.tabStrip)
diff --git a/modules/utils.js b/modules/utils.js
index 9f96ddef..13785723 100644
--- a/modules/utils.js
+++ b/modules/utils.js
@@ -111,6 +111,7 @@ var TreeStyleTabUtils = {
 	kCOUNTER_PAREN         : 'treestyletab-counter-paren',
 	kSPLITTER              : 'treestyletab-splitter',
 	kTABBAR_TOGGLER        : 'treestyletab-tabbar-toggler',
+	kTABBAR_PLACEHOLDER    : 'treestyletab-tabbar-placeholder',
  
 /* other constant values */ 
 	kFOCUS_ALL     : 0,