pinnedなタブは画面内にあると見なす

git-svn-id: http://www.cozmixng.org/repos/piro/treestyletab/trunk@6723 599a83e7-65a4-db11-8015-0010dcdd6dc2

content/treestyletab/treestyletabbrowser.js

@@ -140,6 +140,7 @@ TreeStyleTabBrowser.prototype = {
 	isTabInViewport : function TSTBrowser_isTabInViewport(aTab) 
 	{
 		if (!aTab) return false;
+		if (aTab.pinned) return true;
 		var tabBox = aTab.boxObject;
 		var barBox = this.scrollBox.boxObject;
 		var xOffset = this.getXOffsetOfTab(aTab);