diff --git a/content/treestyletab/treestyletab.css b/content/treestyletab/treestyletab.css
index 1b6df35b..807b8b36 100644
--- a/content/treestyletab/treestyletab.css
+++ b/content/treestyletab/treestyletab.css
@@ -136,7 +136,11 @@ tabbrowser[treestyletab-tabbar-autohide-mode="1"][treestyletab-tabbar-autohide="
 
 
 #treestyletab-autohide-content-area-screen {
-	background: transparent;
+	/**
+	 * don't make this completely transparent, because
+	 * mousemove event never fire on 100% transparent panel!!
+	 */
+	background: rgba(0, 0, 0, 0.01);
 	border: 0 none;
 	line-height: 0;
 	margin: 0;
@@ -148,16 +152,6 @@ tabbrowser[treestyletab-tabbar-autohide-mode="1"][treestyletab-tabbar-autohide="
 	-moz-border-top-colors: none;
 }
 
-#treestyletab-autohide-content-area-screen[popup-shown="true"] {
-	/**
-	 * don't make this completely transparent, because
-	 * mousemove event never fire on 100% transparent panel!!
-	 */
-	background: rgba(0, 0, 0, 0.01);
-	-moz-transition: background-color 0.2s ease-out;
-	transition: background-color 0.2s ease-out;
-}
-
 
 
 /* vertical tab bar */
diff --git a/content/treestyletab/treestyletab.xul b/content/treestyletab/treestyletab.xul
index e9545f9b..7b9d158b 100644
--- a/content/treestyletab/treestyletab.xul
+++ b/content/treestyletab/treestyletab.xul
@@ -151,10 +151,10 @@
 			type="checkbox"
 			autocheck="false"
 			oncommand="TreeStyleTabService.toggleFixed(TreeStyleTabService.getTabBrowserFromChild(this));"/>
-
 	</menupopup>
 	<tooltip id="treestyletab-full-tree-tooltip"/>
 	<panel id="treestyletab-autohide-content-area-screen"
+		onpopupshowing="if ('setConsumeRollupEvent' in this.popupBoxObject) this.popupBoxObject.setConsumeRollupEvent(Components.interfaces.nsIPopupBoxObject.ROLLUP_NO_CONSUME);"
 		onclick="this.hidePopup();"/>
 </popupset>