diff --git a/platform/Linux/chrome.manifest b/platform/Linux/chrome.manifest
index a31ee61b..165e5c54 100644
--- a/platform/Linux/chrome.manifest
+++ b/platform/Linux/chrome.manifest
@@ -1,3 +1 @@
 skin	treestyletab-platform	classic/1.0	jar:chrome/treestyletab.jar!/skin/classic/treestyletab/
-
-style chrome://browser/content/browser.xul chrome://treestyletab-platform/skin/treestyletab-3.5.css appversion>=3.5
diff --git a/platform/Linux/skin/classic/treestyletab/treestyletab-3.5.css b/platform/Linux/skin/classic/treestyletab/treestyletab-3.5.css
deleted file mode 100644
index 9cd1459a..00000000
--- a/platform/Linux/skin/classic/treestyletab/treestyletab-3.5.css
+++ /dev/null
@@ -1,10 +0,0 @@
-@namespace url("http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul");
-
-.tabbrowser-tabs[treestyletab-style~="square"]:not([treestyletab-style="vertigo"])[treestyletab-mode="vertical"]
-  .tabbrowser-tab,
-.tabbrowser-tabs[treestyletab-style~="square"]:not([treestyletab-style="vertigo"])[treestyletab-mode="vertical"]
-  .tabbrowser-arrowscrollbox
-  .tabs-newtab-button {
-	position: relative;
-	z-index: auto;
-}
diff --git a/skin/classic/treestyletab/square/dropshadow.css b/skin/classic/treestyletab/square/dropshadow.css
index 55bbc516..bb9cd71b 100644
--- a/skin/classic/treestyletab/square/dropshadow.css
+++ b/skin/classic/treestyletab/square/dropshadow.css
@@ -106,3 +106,14 @@ tabbrowser[tabberwocky-hidenewtabbutton="true"]
 	background: url("../metal/shadow-inactive-r.png") repeat-y top left !important;
 }
 
+
+/* Transparent tabs are shown above solid tabs.
+   We have to set z-index to show all tabs in the same layer. */
+.tabbrowser-tabs[treestyletab-style~="square"]:not([treestyletab-style="vertigo"])[treestyletab-mode="vertical"]
+  .tabbrowser-tab,
+.tabbrowser-tabs[treestyletab-style~="square"]:not([treestyletab-style="vertigo"])[treestyletab-mode="vertical"]
+  .tabbrowser-arrowscrollbox
+  .tabs-newtab-button {
+	position: relative;
+	z-index: auto;
+}