diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 74f1e2e1..6f717341 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -15,8 +15,7 @@ Here is a list of typical questions I asked to existing reports:
 
  * **Does the problem appear with the [latest develpment build](http://piro.sakura.ne.jp/xul/xpi/nightly/)?**
    Possibly, problems you met has been resolved already.
-   On Firefox 43 and later you need to set `xpinstall.signatures.required` to `false` via `about:config`, to try such unsigned packages of development builds.
-   For Firefox 46 and later, you'll have to try an unbranded Firefox (including Beta, Aurora, and Nightly) to try development builds because the option will be removed on official Firefox 46 and later.
+   On Firefox 48 and later, you'll have to use an [unbranded Firefox](https://wiki.mozilla.org/Add-ons/Extension_Signing#Unbranded_Builds) (including Beta, Aurora, and Nightly) with a secret preference `xpinstall.signatures.required`=`false` (you can set it via `about:config`), to try unsigned development builds.
  * **Does the problem appear without Tab Mix Plus or something other tab related addon?**
    If a compatibility issue with other addons is reported without such information, it is very hard to be resolved.
    See also the next to next.
diff --git a/content/treestyletab/treestyletab-tmp.css b/content/treestyletab/treestyletab-tmp.css
index 8f6b96af..3e46a446 100644
--- a/content/treestyletab/treestyletab-tmp.css
+++ b/content/treestyletab/treestyletab-tmp.css
@@ -21,7 +21,6 @@
 
 :root[treestyletab-enable-compatibility-tmp="true"]
   tabbrowser[treestyletab-mode="vertical"] tabs[flowing] > * .tabs-frame {
-	box-flex: 1 !important;
 	-moz-box-flex: 1 !important;
 }
 
diff --git a/content/treestyletab/treestyletab.css b/content/treestyletab/treestyletab.css
index b9583ea1..c27e3691 100644
--- a/content/treestyletab/treestyletab.css
+++ b/content/treestyletab/treestyletab.css
@@ -60,7 +60,6 @@
 	max-width: 20px;
 	min-width: 20px;
 	width: 20px;
-	box-flex: 0;
 	-moz-box-flex: 0;
 	mask: url("res/tabEffects.svg#fadein-mask");
 }
@@ -171,7 +170,6 @@ tabbrowser[treestyletab-tabbar-autohide-mode="1"][treestyletab-tabbar-autohide="
 
 
 #treestyletab-autohide-content-area-screen {
-	appearance: none;
 	-moz-appearance: none;
 	/**
 	 * Don't make this panel completely transparent, because
@@ -202,9 +200,7 @@ tabbrowser[treestyletab-tabbar-autohide-mode="1"][treestyletab-tabbar-autohide="
 .tabbrowser-tabs[treestyletab-mode="vertical"]
   .tabbrowser-arrowscrollbox
   .scrollbox-innerbox {
-	box-flex: 1 !important;
 	-moz-box-flex: 1 !important;
-	box-pack: start !important;
 	-moz-box-pack: start !important;
 }
 
@@ -218,7 +214,6 @@ toolbar.treestyletab-tabbar-toolbar[treestyletab-mode="vertical"]
   > toolbaritem,
 toolbar.treestyletab-tabbar-toolbar[treestyletab-mode="vertical"]
   > .treestyletab-toolbar-inner-box > toolbaritem {
-	box-flex: 0 !important;
 	-moz-box-flex: 0 !important;
 }
 
@@ -229,7 +224,6 @@ toolbar.treestyletab-tabbar-toolbar[treestyletab-mode="vertical"]
 
 /* workaround for https://github.com/piroor/treestyletab/issues/100 */
 .treestyletab-tabbar-toolbar[treestyletab-mode="vertical"] .textbox-input-box {
-	box-align: stretch;
 	-moz-box-align: stretch;
 }
 
@@ -286,7 +280,7 @@ tabs.tabbrowser-tabs[treestyletab-tabbar-position="left"][treestyletab-invert-sc
 	min-height: 1px !important;
 	opacity: 0 !important;
 	/**
-	 * Sometimes "transitionend" event for "max-width" doesn't fire so ghotst
+	 * Sometimes "transitionend" event for "max-width" doesn't fire so ghost
 	 * tabs are left. To do cleanup process forcedly, we have to re-define new
 	 * max-width to fire transitionend event.
 	 */
@@ -421,7 +415,6 @@ toolbar.treestyletab-tabbar-toolbar-ready:not([nowindowdrag="true"]),
 
 .treestyletab-tabbar-toolbar:not([treestyletab-tabbar-position="top"]),
 .treestyletab-tabbar-toolbar[treestyletab-tabbar-position="top"]:not([treestyletab-tabbar-fixed="true"]) {
-	appearance: none !important;
 	-moz-appearance: none !important;
 	line-height: 0 !important; /* to avoid an useless space above the tab bar */
 	position: fixed !important;
diff --git a/modules/window.js b/modules/window.js
index 28a2f41d..b3a3e401 100644
--- a/modules/window.js
+++ b/modules/window.js
@@ -20,6 +20,7 @@
  * Contributor(s): YUKI "Piro" Hiroshi <piro.outsider.reflex@gmail.com>
  *                 Tetsuharu OHZEKI <https://github.com/saneyuki>
  *                 J. Ryan Stinnett <https://github.com/jryans>
+ *                 Ohnuma <https://github.com/lv7777>
  *
  * Alternatively, the contents of this file may be used under the terms of
  * either the GNU General Public License Version 2 or later (the "GPL"), or
@@ -95,6 +96,13 @@ function TreeStyleTabWindow(aWindow)
 	aWindow.TreeStyleTabService = this;
 
 	XPCOMUtils.defineLazyModuleGetter(aWindow, 'TreeStyleTabBrowser', 'resource://treestyletab-modules/browser.js');
+
+	var isDevEdition = this.window.AppConstants.MOZ_DEV_EDITION;
+	if (isDevEdition) {
+		let rootelem = this.document.documentElement;
+		rootelem.setAttribute('treestyletab-devedition', true);
+	}
+
 }
 
 TreeStyleTabWindow.prototype = inherit(TreeStyleTabBase, {
diff --git a/skin/classic/treestyletab/Linux-base.css b/skin/classic/treestyletab/Linux-base.css
index 04ba193e..701f5d67 100644
--- a/skin/classic/treestyletab/Linux-base.css
+++ b/skin/classic/treestyletab/Linux-base.css
@@ -2,7 +2,6 @@
 
 /* splitter for floating & autohide tab bar */
 .treestyletab-tabbar-toolbar .treestyletab-splitter {
-	appearance: none;
 	-moz-appearance: none;
 	width: 6px;
 }
diff --git a/skin/classic/treestyletab/Linux-styled.css b/skin/classic/treestyletab/Linux-styled.css
index bd0dd49b..0e5e3cf4 100644
--- a/skin/classic/treestyletab/Linux-styled.css
+++ b/skin/classic/treestyletab/Linux-styled.css
@@ -8,7 +8,6 @@
 .tabbrowser-tabs[treestyletab-tabbar-position="top"][treestyletab-tabs-indented="true"]
   .tabbrowser-tab[visuallyselected="true"] {
 	border-radius: 0 0 0 0;
-	-moz-border-radius: 0 0 0 0;
 	height: 1.5em;
 	margin-bottom: 0;
 	padding-bottom: 0;
diff --git a/skin/classic/treestyletab/WINNT-styled.css b/skin/classic/treestyletab/WINNT-styled.css
index c159009f..49d87d9f 100644
--- a/skin/classic/treestyletab/WINNT-styled.css
+++ b/skin/classic/treestyletab/WINNT-styled.css
@@ -9,7 +9,6 @@
 .tabbrowser-tabs[treestyletab-tabbar-position="top"][treestyletab-tabs-indented="true"]
   .tabbrowser-tab:hover[visuallyselected="true"] {
 	border-radius: 0 0 0 0;
-	-moz-border-radius: 0 0 0 0;
 	border-top-width: 1px;
 	height: auto;
 	margin-bottom: 3px;
diff --git a/skin/classic/treestyletab/base-colors.css b/skin/classic/treestyletab/base-colors.css
index fbfb9ffe..c2d071ee 100644
--- a/skin/classic/treestyletab/base-colors.css
+++ b/skin/classic/treestyletab/base-colors.css
@@ -44,7 +44,7 @@
 	--tst-tab-dropmarker: -moz-dialogtext;
 }
 
-:root[devtoolstheme="dark"] {
+:root[devtoolstheme="dark"][treestyletab-devedition="true"] {
 	--tst-tab-surface: #39424D;
 	--tst-tab-text: white;
 	--tst-tab-border: #5f6670;
diff --git a/skin/classic/treestyletab/base.css b/skin/classic/treestyletab/base.css
index d164eb4f..3563df52 100644
--- a/skin/classic/treestyletab/base.css
+++ b/skin/classic/treestyletab/base.css
@@ -42,7 +42,6 @@
 .tabbrowser-tabs[treestyletab-mode="vertical"] .tabs-newtab-button,
 .treestyletab-tabbar-toolbar[treestyletab-mode="vertical"] > toolbarbutton,
 .treestyletab-tabbar-toolbar[treestyletab-mode="vertical"] > toolbarpaletteitem > toolbarbutton {
-	appearance: none !important;
 	-moz-appearance: none !important;
 	border: 0 none !important;
 	-moz-border-top-colors: none !important;
@@ -50,7 +49,6 @@
 	-moz-border-bottom-colors: none !important;
 	-moz-border-left-colors: none !important;
 	border-radius: 0;
-	-moz-border-radius: 0;
 	border-top: 1px solid var(--tst-tab-border) !important;
 	background: var(--tst-tab-surface) !important;
 }
@@ -76,7 +74,6 @@
 
 /* Support customizable tab bar */
 .treestyletab-tabbar-toolbar[treestyletab-mode="vertical"] > toolbarpaletteitem > toolbarbutton {
-	box-flex: 1;
 	-moz-box-flex: 1;
 }
 .treestyletab-tabbar-toolbar[treestyletab-mode="vertical"] > *:not(toolbarpaletteitem) {
@@ -111,7 +108,6 @@
 	border: 0 none !important;
 	border-bottom: 1px solid var(--tst-tab-border) !important;
 	border-radius: 0 0 3px 3px;
-	-moz-border-radius: 0 0 3px 3px;
 }
 .tabbrowser-tabs[treestyletab-style~="vertigo"][treestyletab-mode="vertical"]
   .tabbrowser-arrowscrollbox .tabs-newtab-button {
diff --git a/skin/classic/treestyletab/config.css b/skin/classic/treestyletab/config.css
index b954604f..859d7ac7 100644
--- a/skin/classic/treestyletab/config.css
+++ b/skin/classic/treestyletab/config.css
@@ -2,7 +2,6 @@
 
 radio.image .radio-label-box,
 radio.image label.radio-label {
-	box-align: center;
 	-moz-box-align: center;
 }
 
diff --git a/skin/classic/treestyletab/group.css b/skin/classic/treestyletab/group.css
index 44762f02..756c3bb5 100644
--- a/skin/classic/treestyletab/group.css
+++ b/skin/classic/treestyletab/group.css
@@ -1,7 +1,6 @@
 @namespace url("http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul");
 
 :root {
-	appearance: window;
 	-moz-appearance: window;
 	background: -moz-dialog;
 	margin: 0;
@@ -46,7 +45,6 @@
 	image-rendering: -moz-crisp-edges;
 	margin: 0 -0.3em -0.3em 0;
 	transform: rotate(8deg);
-	-moz-transform: rotate(8deg);
 }
 
 .background-image-container {
@@ -61,7 +59,6 @@
 #tree {
 	margin: 1em 0 0 0.5em;
 	overflow: auto;
-	box-flex: 1;
 	-moz-box-flex: 1;
 }
 
diff --git a/skin/classic/treestyletab/metal/aero.css b/skin/classic/treestyletab/metal/aero.css
index b364a489..8714f639 100644
--- a/skin/classic/treestyletab/metal/aero.css
+++ b/skin/classic/treestyletab/metal/aero.css
@@ -5,7 +5,6 @@
 tabbrowser[treestyletab-style~="aero"]:not([treestyletab-tabbar-position="top"]),
 :root[treestyletab-style~="aero"]:not([treestyletab-tabbar-position="top"]) #appcontent,
 :root[treestyletab-style~="aero"]:not([treestyletab-tabbar-position="top"]) #browser {
-	appearance: none !important;
 	-moz-appearance: none !important;
 	background: transparent !important;
 }
diff --git a/skin/classic/treestyletab/metal/base.css b/skin/classic/treestyletab/metal/base.css
index d259246f..f58315e9 100644
--- a/skin/classic/treestyletab/metal/base.css
+++ b/skin/classic/treestyletab/metal/base.css
@@ -4,12 +4,10 @@
 
 .treestyletab-tabbar-toolbar:not([treestyletab-tabbar-position="top"]),
 .treestyletab-tabbar-toolbar[treestyletab-tabbar-position="top"]:not([treestyletab-tabbar-fixed="true"]) {
-	appearance: none !important;
 	-moz-appearance: none !important;
 	background: transparent !important;
 	border: 0 none !important;
 	box-shadow: none !important;
-	-moz-box-shadow: none !important;
 	margin: 0 !important;
 	padding: 0 !important;
 }
@@ -42,7 +40,6 @@
 }
 
 .tabbrowser-tabs[treestyletab-mode="vertical"] {
-	appearance: none !important;
 	-moz-appearance: none !important;
 	background: transparent !important;
 	margin: 0;
@@ -78,7 +75,6 @@ tabbrowser[treestyletab-mode="vertical"]
   .treestyletab-splitter,
 .treestyletab-tabbar-toolbar[treestyletab-mode="vertical"]
   .treestyletab-splitter {
-	appearance: none !important;
 	-moz-appearance: none !important;
 	background: #b3b2b3 !important;
 	border: 0 solid #666666 !important;
@@ -286,14 +282,13 @@ tabbrowser[treestyletab-tabbar-position="right"]
 	background: #9a9a9a url("shadow-active-l.png") repeat-y top right !important;
 	margin-left: 6px !important;
 	border-radius: 6px 0 0 6px;
-	-moz-border-radius: 6px 0 0 6px;
 }
 .tabbrowser-tabs[treestyletab-mode="vertical"][treestyletab-tab-inverted="true"]
   .tabbrowser-arrowscrollbox
   .tabs-newtab-button {
 	background: #9a9a9a url("shadow-active-r.png") repeat-y top left !important;
 	margin-right: 6px !important;
-	-moz-border-radius: 0 6px 6px 0;
+	border-radius: 0 6px 6px 0;
 }
 
 .tabbrowser-tabs[treestyletab-tabbar-position="left"]
diff --git a/skin/classic/treestyletab/metal/tab.css b/skin/classic/treestyletab/metal/tab.css
index 90a7953b..05546d3a 100644
--- a/skin/classic/treestyletab/metal/tab.css
+++ b/skin/classic/treestyletab/metal/tab.css
@@ -8,11 +8,9 @@
   .tabbrowser-tab[visuallyselected="true"],
 .tabbrowser-tabs[treestyletab-mode="vertical"]
   .tabbrowser-tab[visuallyselected="true"]:hover {
-	appearance: none !important;
 	-moz-appearance: none !important;
 	border: 2px solid transparent !important;
 	border-radius: 0 !important;
-	-moz-border-radius: 0 !important;
 	color: black !important;
 	height: auto !important;
 	max-height: none !important;
@@ -113,7 +111,6 @@
 }
 .tabbrowser-tabs[treestyletab-mode="vertical"]
   .tab-content {
-	appearance: none !important;
 	-moz-appearance: none !important;
 	border: 10px solid transparent;
 	margin: 0 !important;
@@ -226,7 +223,6 @@
   .tabbrowser-tab[pinned][visuallyselected="true"]:hover {
 	border: none !important;
 	border-radius: 0 !important;
-	-moz-border-radius: 0 !important;
 	padding: 0 !important;
 }
 .tabbrowser-tabs[treestyletab-mode="vertical"]
@@ -263,7 +259,6 @@
 	line-height: 1 !important;
 	border: 1px solid #666666 !important;
 	border-radius: 4px !important;
-	-moz-border-radius: 4px !important;
 	margin: 1px 0 0 1px !important;
 	padding: 2px 4px 2px 3px !important;
 }
diff --git a/skin/classic/treestyletab/sidebar/aero.css b/skin/classic/treestyletab/sidebar/aero.css
index 3cb6e067..ec91a63e 100644
--- a/skin/classic/treestyletab/sidebar/aero.css
+++ b/skin/classic/treestyletab/sidebar/aero.css
@@ -5,7 +5,6 @@
 tabbrowser[treestyletab-style~="aero"]:not([treestyletab-tabbar-position="top"]),
 :root[treestyletab-style~="aero"]:not([treestyletab-tabbar-position="top"]) #appcontent,
 :root[treestyletab-style~="aero"]:not([treestyletab-tabbar-position="top"]) #browser {
-	appearance: none !important;
 	-moz-appearance: none !important;
 	background: transparent !important;
 }
diff --git a/skin/classic/treestyletab/sidebar/sidebar.css b/skin/classic/treestyletab/sidebar/sidebar.css
index 0dbaae59..1e2c159e 100644
--- a/skin/classic/treestyletab/sidebar/sidebar.css
+++ b/skin/classic/treestyletab/sidebar/sidebar.css
@@ -108,13 +108,10 @@ tabbrowser[treestyletab-mode="vertical"]
 /* Style tabs themselves.  Get rid of most of the initial XUL styling */
 .tabbrowser-tabs[treestyletab-mode="vertical"]
   .tabbrowser-tab {
-	appearance: none !important;
 	-moz-appearance: none !important;
 	border: none;
 	border-radius: 0 !important;
-	-moz-border-radius: 0 !important;
 	border-top: 1px solid transparent !important;
-	box-align: stretch !important;
 	-moz-box-align: stretch !important;
 	height: 21px !important;     /* height including border! */
 	margin: 0 !important;
@@ -231,7 +228,6 @@ tabbrowser[treestyletab-mode="vertical"]
   .treestyletab-counter-container {
 	background-color: #91a0c0 !important;
 	border-radius: 8px !important;
-	-moz-border-radius: 8px !important;
 	padding: 0 6px !important;
 }
 .tabbrowser-tabs[treestyletab-mode="vertical"]
@@ -295,7 +291,6 @@ tabbrowser[treestyletab-mode="vertical"]
 	background: #d0def5 !important;
 	border: 2px solid #577bf3 !important; /* not OSX's colour but Firefox's */
 	border-radius: 8px !important;
-	-moz-border-radius: 8px !important;
 	padding: 0 1px 0 8px !important;
 }
 
@@ -334,12 +329,10 @@ tabbrowser[treestyletab-mode="vertical"]
 
 .treestyletab-tabbar-toolbar:not([treestyletab-tabbar-position="top"]),
 .treestyletab-tabbar-toolbar[treestyletab-tabbar-position="top"]:not([treestyletab-tabbar-fixed="true"]) {
-	appearance: none !important;
 	-moz-appearance: none !important;
 	background: transparent !important;
 	border: 0 none !important;
 	box-shadow: none !important;
-	-moz-box-shadow: none !important;
 	margin: 0 !important;
 	padding: 0 !important;
 }
@@ -363,7 +356,6 @@ tabbrowser[treestyletab-mode="vertical"]
 .treestyletab-tabbar-toolbar[treestyletab-mode="vertical"]
   > toolbarpaletteitem
   > toolbarbutton:hover {
-	appearance: none !important;
 	-moz-appearance: none !important;
 	background: transparent !important;
 	border: 0 none !important;
@@ -399,7 +391,6 @@ tabbrowser[treestyletab-mode="vertical"]
 	-moz-image-region: auto !important;
 }
 .tabbrowser-tabs[treestyletab-mode="vertical"] {
-	appearance: none !important;
 	-moz-appearance: none !important;
 	background: transparent !important;
 	margin: 0;
@@ -408,7 +399,6 @@ tabbrowser[treestyletab-mode="vertical"]
 /* for Linux (Gnomestrip) */
 .tabbrowser-tabs[treestyletab-mode="vertical"]
   .tab-close-button {
-	appearance: none !important;
 	-moz-appearance: none !important;
 }
 
diff --git a/skin/classic/treestyletab/square/base.css b/skin/classic/treestyletab/square/base.css
index 3f6dff9a..2ba259c8 100644
--- a/skin/classic/treestyletab/square/base.css
+++ b/skin/classic/treestyletab/square/base.css
@@ -15,7 +15,7 @@
 	--tst-tabbar-bg: darkgray;
 }
 
-:root[devtoolstheme="dark"] {
+:root[devtoolstheme="dark"][treestyletab-devedition="true"] {
 	--tst-tab-highlighted-base: ThreeDHighlight;
 	--tst-tab-highlighted-highlight: Highlight;
 	--tst-tab-side-border: #39424D;
@@ -31,14 +31,12 @@
 
 .tabbrowser-tabs:not([treestyletab-tabbar-position="top"]),
 .treestyletab-tabbar-toolbar:not([treestyletab-tabbar-position="top"]) {
-	appearance: none;
 	-moz-appearance: none;
 	background: transparent !important;
 	margin: 0 !important;
 	padding: 0 !important;
 }
 .tabbrowser-strip[treestyletab-style~="border"]:not([treestyletab-tabbar-position="top"]) {
-	appearance: none;
 	-moz-appearance: none;
 	background: var(--tst-tabbar-bg) !important;
 }
@@ -62,7 +60,6 @@
 	margin: 0 !important;
 	padding: 0 !important;
 	box-shadow: none !important;
-	-moz-box-shadow: none !important;
 }
 
 .tabbrowser-strip[treestyletab-tabbar-position="left"][treestyletab-tabbar-fixed="true"],
@@ -114,7 +111,6 @@
   .tabbrowser-tab[visuallyselected="true"],
 .tabbrowser-tabs:not([treestyletab-tabbar-position="top"])
   .tabbrowser-tab:not([visuallyselected="true"]) {
-	appearance: none !important;
 	-moz-appearance: none !important;
 	min-height: 2em;
 	margin: 0 !important;
@@ -128,10 +124,8 @@
 	border-bottom: 2px solid !important;
 	-moz-border-bottom-colors: var(--tst-tab-border) transparent !important;
 	border-radius: 0 !important;
-	-moz-border-radius: 0 !important;
 	-moz-border-image: none !important;
 	border-image: none !important;
-	box-align: stretch !important;
 	-moz-box-align: stretch !important;
 }
 /* override "-moz-menutext" color defined by the default theme, because it is too bright on Ubuntu */
@@ -297,7 +291,6 @@
 /* Mac OS X */
 .tabbrowser-tabs[treestyletab-mode="vertical"]
   .tabbrowser-tab {
-	box-pack: start !important;
 	-moz-box-pack: start !important;
 	text-align: start !important; 
 }
@@ -326,7 +319,6 @@
 tabbrowser[treestyletab-style~="aero"]:not([treestyletab-tabbar-position="top"]),
 :root[treestyletab-style~="aero"]:not([treestyletab-tabbar-position="top"]) #appcontent,
 :root[treestyletab-style~="aero"]:not([treestyletab-tabbar-position="top"]) #browser {
-	appearance: none !important;
 	-moz-appearance: none !important;
 	background: transparent !important;
 }
diff --git a/skin/classic/treestyletab/square/dropshadow.css b/skin/classic/treestyletab/square/dropshadow.css
index 3c6ab5dd..0993f0b7 100644
--- a/skin/classic/treestyletab/square/dropshadow.css
+++ b/skin/classic/treestyletab/square/dropshadow.css
@@ -6,13 +6,11 @@
 .tabbrowser-tabs[treestyletab-mode="vertical"]
   .tabbrowser-tab:not([pinned="true"]) {
 	box-shadow: -0.3em 0.3em 0.2em rgba(0, 0, 0, 0.15);
-	-moz-box-shadow: -0.3em 0.3em 0.2em rgba(0, 0, 0, 0.15);
 }
 
 .tabbrowser-tabs[treestyletab-mode="vertical"][treestyletab-tab-inverted="true"]
   .tabbrowser-tab:not([pinned="true"]) {
 	box-shadow: 0.3em 0.3em 0.2em rgba(0, 0, 0, 0.15);
-	-moz-box-shadow: 0.3em 0.3em 0.2em rgba(0, 0, 0, 0.15);
 }
 
 .tabbrowser-tabs[treestyletab-mode="vertical"]
@@ -24,7 +22,6 @@
   .tabbrowser-arrowscrollbox
   .tabs-newtab-button {
 	box-shadow: 0 0.3em 0.2em rgba(0, 0, 0, 0.15);
-	-moz-box-shadow: 0 0.3em 0.2em rgba(0, 0, 0, 0.15);
 }
 
 
@@ -34,7 +31,6 @@
   .tabbrowser-arrowscrollbox
   .scrollbox-innerbox {
 	box-shadow: inset -0.2em 0.2em 0.3em rgba(0, 0, 0, 0.15) !important;
-	-moz-box-shadow: inset -0.2em 0.2em 0.3em rgba(0, 0, 0, 0.15) !important;
 }
 
 .tabbrowser-tabs[treestyletab-mode="vertical"][treestyletab-tab-inverted="true"]:not([overflow="true"])
@@ -43,7 +39,6 @@
   .tabbrowser-arrowscrollbox
   .scrollbox-innerbox {
 	box-shadow: inset 0.2em 0.2em 0.3em rgba(0, 0, 0, 0.15) !important;
-	-moz-box-shadow: inset 0.2em 0.2em 0.3em rgba(0, 0, 0, 0.15) !important;
 }
 
 
diff --git a/skin/classic/treestyletab/tmp.css b/skin/classic/treestyletab/tmp.css
index bf03a25b..167d7f9e 100644
--- a/skin/classic/treestyletab/tmp.css
+++ b/skin/classic/treestyletab/tmp.css
@@ -38,7 +38,6 @@
 
 :root[treestyletab-enable-compatibility-tmp="true"]
   .tabbrowser-tabs[treestyletab-mode="vertical"] .tabs-closebutton-topbox > .tabs-closebutton {
-	appearance: none !important;
 	-moz-appearance: none !important;
 	border: 0 none !important;
 	-moz-border-top-colors: none !important;
@@ -66,13 +65,9 @@
 
 :root[treestyletab-enable-compatibility-tmp="true"]
   .tabbrowser-tabs[treestyletab-mode="vertical"] .tabs-newtab-topbox > .tabs-newtab-button {
-	box-flex: 1;
 	-moz-box-flex: 1;
-	box-align: center;
 	-moz-box-align: center;
-	box-pack: center;
 	-moz-box-pack: center;
-	box-orient: vertical;
 	-moz-box-orient: vertical;
 }
 
diff --git a/skin/classic/treestyletab/twisty/twisty.css b/skin/classic/treestyletab/twisty/twisty.css
index 2d4bd790..2b30bb41 100644
--- a/skin/classic/treestyletab/twisty/twisty.css
+++ b/skin/classic/treestyletab/twisty/twisty.css
@@ -12,11 +12,8 @@
 	max-width: 16px;
 	min-height: 16px;
 	min-width: 16px;
-	box-pack: start;
 	-moz-box-pack: start;
-	box-align: center;
 	-moz-box-align: center;
-	box-flex: 1;
 	-moz-box-flex: 1;
 }
 
diff --git a/skin/classic/treestyletab/ui-base.css b/skin/classic/treestyletab/ui-base.css
index efbc78d4..3b730f06 100644
--- a/skin/classic/treestyletab/ui-base.css
+++ b/skin/classic/treestyletab/ui-base.css
@@ -3,9 +3,7 @@
 /* tree UI */
 
 .treestyletab-counter-container {
-	box-align: center;
 	-moz-box-align: center;
-	box-pack: end;
 	-moz-box-pack: end;
 }
 
@@ -165,7 +163,6 @@
 
 
 tabbrowser[treestyletab-drop-position] {
-	appearance: none !important;
 	-moz-appearance: none !important;
 	border: 2px solid transparent !important;
 	-moz-border-top-colors: none !important;
@@ -306,7 +303,6 @@ tabbrowser[treestyletab-tabbar-position="bottom"]
 /* toolbar customization */
 
 .treestyletab-tabbar-toolbar-ready-popup {
-	appearance: tooltip;
 	-moz-appearance: tooltip;
 	max-width: 15em;
 	opacity: 0.85;
@@ -320,7 +316,6 @@ tabbrowser[treestyletab-tabbar-position="bottom"]
 
 /* pinned tabs */
 .tabbrowser-tabs[treestyletab-mode="vertical"][positionpinnedtabs="true"] {
-	padding-start: 0 !important;
 	-moz-padding-start: 0 !important;
 }
 
@@ -344,18 +339,14 @@ tabbrowser[treestyletab-tabbar-position="bottom"]
   .tabbrowser-tab[pinned="true"] .tab-stack,
 .tabbrowser-tabs[treestyletab-mode="vertical"]
   .tab-content[pinned="true"] {
-	box-align: center;
 	-moz-box-align: center;
-	box-pack: center;
 	-moz-box-pack: center;
 	min-height: 0;
 }
 
 .tabbrowser-tabs[treestyletab-mode="vertical"]
   .tab-background[pinned="true"] {
-	box-align: stretch;
 	-moz-box-align: stretch;
-	box-pack: justify;
 	-moz-box-pack: justify;
 	min-height: 0;
 }
@@ -403,7 +394,6 @@ tabbrowser[treestyletab-tabbar-position="bottom"]
 	border: 0 none;
 	bottom: 0;
 	box-shadow: none;
-	-moz-box-shadow: none;
 	height: 2em;
 	left: 0;
 	margin-top: -2em;
@@ -414,8 +404,6 @@ tabbrowser[treestyletab-tabbar-position="bottom"]
 	right: 0;
 	top: 0;
 	transition: 1s opacity ease-out;
-	transition: 1s opacity ease-out;
-	user-focus: ignore;
 	z-index: 99999;
 	-moz-user-focus: ignore;
 }
@@ -436,7 +424,6 @@ tabbrowser[treestyletab-tabbar-position="bottom"]
 	outline: transparent solid 0.2em;
 	outline-offset: -0.2em;
 	-moz-outline-radius: 0.25em;
-	outline-radius: 0.25em;
 }
 .tabbrowser-tab[treestyletab-highlighted='notifying'] {
 	outline: Highlight solid 0.2em;