diff --git a/skin/classic/treestyletab/metal/tab-base.css b/skin/classic/treestyletab/metal/tab-base.css
index 3b1880df..82c227cd 100644
--- a/skin/classic/treestyletab/metal/tab-base.css
+++ b/skin/classic/treestyletab/metal/tab-base.css
@@ -51,6 +51,12 @@
   .tab-background-end::after {
 	display: none !important;
 }
+.tabbrowser-tabs:not([treestyletab-tabbar-position="top"])
+  :-moz-any(.tab-background-start,
+            .tab-background-end) {
+  min-height: 0;
+  width: 0;
+}
 
 /* for Mac OS X */
 .tabbrowser-tabs[treestyletab-mode="vertical"]
diff --git a/skin/classic/treestyletab/sidebar/sidebar-base.css b/skin/classic/treestyletab/sidebar/sidebar-base.css
index 92630ce3..5c25615c 100644
--- a/skin/classic/treestyletab/sidebar/sidebar-base.css
+++ b/skin/classic/treestyletab/sidebar/sidebar-base.css
@@ -61,6 +61,12 @@
   .tab-background-end::after {
 	display: none !important;
 }
+.tabbrowser-tabs:not([treestyletab-tabbar-position="top"])
+  :-moz-any(.tab-background-start,
+            .tab-background-end) {
+  min-height: 0;
+  width: 0;
+}
 
 /* Use the splitter to display the border of .tabbrowser-strip */
 tabbrowser[treestyletab-mode="vertical"]
diff --git a/skin/classic/treestyletab/square/base.css b/skin/classic/treestyletab/square/base.css
index 1c113a08..8024f103 100644
--- a/skin/classic/treestyletab/square/base.css
+++ b/skin/classic/treestyletab/square/base.css
@@ -69,6 +69,12 @@
   .tab-background-end::after {
 	display: none !important;
 }
+.tabbrowser-tabs:not([treestyletab-tabbar-position="top"])
+  :-moz-any(.tab-background-start,
+            .tab-background-end) {
+  min-height: 0;
+  width: 0;
+}
 
 .tabbrowser-tabs:not([treestyletab-tabbar-position="top"])
   .tabbrowser-tab,