diff --git a/content/treestyletab/treestyletab.css b/content/treestyletab/treestyletab.css
index 0adf1d4f..7558971b 100644
--- a/content/treestyletab/treestyletab.css
+++ b/content/treestyletab/treestyletab.css
@@ -87,8 +87,7 @@ tabbrowser[treestyletab-mode="vertical"] .tabs-stack > *:first-child + * > hbox:
 	width: 24px !important;
 	height: 24px !important;
 }
-.tabbrowser-tabs[treestyletab-mode="vertical"]
-	.tabbrowser-tab[pinned="true"] .tab-text {
+.tabbrowser-tab[pinned="true"] .tab-text {
 	visibility: collapse !important;
 }
 
diff --git a/content/treestyletab/treestyletabbrowser.js b/content/treestyletab/treestyletabbrowser.js
index 7f50a5a1..37dd8aa3 100644
--- a/content/treestyletab/treestyletabbrowser.js
+++ b/content/treestyletab/treestyletabbrowser.js
@@ -166,12 +166,14 @@ TreeStyleTabBrowser.prototype = {
 		var maxRow = Math.ceil(count / maxCol);
 		var col    = 0;
 		var row    = 0;
+		tabbar.style.MozMarginStart = '';
 		tabbar.style.marginTop = (height * maxRow)+'px';
-		for (var i = 0, count; i < count; i++)
+		for (var i = 0; i < count; i++)
 		{
-			let tab = tabbar.childNodes[i];
-			tab.style.setProperty('margin-left', (width * col)+'px', 'important');
-			tab.style.setProperty('margin-top', (- height * (maxRow - row))+'px', 'important');
+			let style = tabbar.childNodes[i].style;
+			style.MozMarginStart = '';
+			style.setProperty('margin-left', (width * col)+'px', 'important');
+			style.setProperty('margin-top', (- height * (maxRow - row))+'px', 'important');
 			col++;
 			if (col >= maxCol) {
 				col = 0;
@@ -181,6 +183,29 @@ TreeStyleTabBrowser.prototype = {
 	},
 	PINNED_TAB_WIDTH : 24,
 	PINNED_TAB_HEIGHT : 24,
+ 
+	clearPinnedTabsAppearance : function TSTBrowser_clearPinnedTabsAppearance() 
+	{
+		var b = this.mTabBrowser;
+		var tabbar = b.tabContainer;
+		tabbar.style.MozMarginStart = '';
+		tabbar.style.marginTop = '';
+		for (var i = 0, count = b._numPinnedTabs; i < count; i++)
+		{
+			let style = tabbar.childNodes[i].style;
+			style.MozMarginStart = '';
+			style.marginLeft = '';
+			style.marginTop = '';
+		}
+	},
+ 
+	onUnpinTab : function TSTBrowser_onUnpinTab(aTab) 
+	{
+		if (!this.isVertical)
+			return;
+		aTab.style.marginLeft = '';
+		aTab.style.marginTop = '';
+	},
   
 /* initialize */ 
 	
@@ -416,6 +441,7 @@ TreeStyleTabBrowser.prototype = {
 							this.tabbrowser.treeStyleTab.positionVerticalPinnedTabs();
 						}
 						else {
+							this.tabbrowser.treeStyleTab.clearPinnedTabsAppearance();
 					]]>.toString()
 				).replace(
 					'this.mTabstrip.ensureElementIsVisible',
@@ -424,6 +450,17 @@ TreeStyleTabBrowser.prototype = {
 			);
 		}
 
+		if (b.unpinTab) {
+			eval('b.unpinTab = '+
+				b.unpinTab.toSource().replace(
+					'this.tabContainer._positionPinnedTabs',
+					<![CDATA[
+						this.treeStyleTab.onUnpinTab(aTab);
+					$&]]>.toString()
+				)
+			);
+		}
+
 		TreeStyleTabService.updateTabDNDObserver(b);
 
 		if (b.tabContainer && '_getDropIndex' in b.tabContainer) { // Firefox 3.7 or later