diff --git a/skin/classic/treestyletab/sidebar/sidebar.css b/skin/classic/treestyletab/sidebar/sidebar.css
index 5ec4d465..c76c80fb 100644
--- a/skin/classic/treestyletab/sidebar/sidebar.css
+++ b/skin/classic/treestyletab/sidebar/sidebar.css
@@ -174,6 +174,13 @@ tabbrowser[treestyletab-style="sidebar"][treestyletab-mode="vertical"]
   border: 0 none !important;
 }
 
+/* for rightside tab bar: "display:none" breaks the order of tab contents. */
+tabbrowser[treestyletab-style="sidebar"][treestyletab-mode="vertical"]
+.tabbrowser-tab:not(:hover):not([selected="true"]) > .tab-close-button {
+  display: -moz-box !important;
+  visibility: collapse !important;
+}
+
 /* for Windows (Winstrip/Strata) */
 tabbrowser[treestyletab-style="sidebar"][treestyletab-mode="vertical"]
   .tab-close-button image,
@@ -199,5 +206,5 @@ tabbrowser[treestyletab-style="sidebar"][treestyletab-mode="vertical"]
 /* for Multiple Tab Handler */
 tabbrowser[treestyletab-style="sidebar"][treestyletab-mode="vertical"]
   .tabbrowser-tab:not(:hover):not([selected="true"])[multipletab-ready-to-close="true"] > .tab-close-button {
-  display: -moz-box !important;
+  visibility: visible !important;
 }
diff --git a/skin/classic/treestyletab/twisty/twisty-osx-l.png b/skin/classic/treestyletab/twisty/twisty-osx-l.png
index de1946ad..7c980ff7 100644
Binary files a/skin/classic/treestyletab/twisty/twisty-osx-l.png and b/skin/classic/treestyletab/twisty/twisty-osx-l.png differ
diff --git a/skin/classic/treestyletab/twisty/twisty-osx-r.png b/skin/classic/treestyletab/twisty/twisty-osx-r.png
index 90b39550..d99232f8 100644
Binary files a/skin/classic/treestyletab/twisty/twisty-osx-r.png and b/skin/classic/treestyletab/twisty/twisty-osx-r.png differ