diff --git a/modules/browser.js b/modules/browser.js
index 81efc649..45f4ebad 100644
--- a/modules/browser.js
+++ b/modules/browser.js
@@ -1820,19 +1820,19 @@ TreeStyleTabBrowser.prototype = {
 		var splitter = this.splitter;
 		if (splitter.collapsed || splitter.getAttribute('state') != 'collapsed') {
 			let shouldAutoHideForSingleTab = (
-			(
-				// "autohide for single tab" feature is removed on Firefox 23.
-				// https://bugzilla.mozilla.org/show_bug.cgi?id=855370
 				(
-					prefs.getDefaultPref('browser.tabs.autoHide') !== null ||
-					// but "Hide Tab Bar With One Tab" provides it.
-					// https://addons.mozilla.org/firefox/addon/hide-tab-bar-with-one-tab/
-					'hideTabBar' in this.window
-				) &&
-				prefs.getPref('browser.tabs.autoHide')
-			) ||
-			// Tab Mix Plus also provides it.
-			'TabmixTabbar' in this.window && this.window.TabmixTabbar.hideMode > 0
+					// "autohide for single tab" feature is removed on Firefox 23.
+					// https://bugzilla.mozilla.org/show_bug.cgi?id=855370
+					(
+						prefs.getDefaultPref('browser.tabs.autoHide') !== null ||
+						// but "Hide Tab Bar With One Tab" provides it.
+						// https://addons.mozilla.org/firefox/addon/hide-tab-bar-with-one-tab/
+						'hideTabBar' in this.window
+					) &&
+					prefs.getPref('browser.tabs.autoHide')
+				) ||
+				// Tab Mix Plus also provides it.
+				'TabmixTabbar' in this.window && this.window.TabmixTabbar.hideMode > 0
 			);
 			this._tabStripPlaceHolder.collapsed =
 				splitter.collapsed =