Index: typo3/js/pagetreefiltermenu.js
===================================================================
--- typo3/js/pagetreefiltermenu.js	(revision 7740)
+++ typo3/js/pagetreefiltermenu.js	(working copy)
@@ -46,6 +46,7 @@
 	toggleMenu: function(event) {
 		var toolbarItem = Ext.get('tree-toolbar-filter-item');
 		var treeFilterBox = Ext.get('treeFilterBox');
+		var treeFilterItem = Ext.get('treeFilter');
 		var treeFilterReset = Ext.get('treeFilterReset');
 
 		toolbarItem.blur();
@@ -55,6 +56,7 @@
 			treeFilterReset.fadeOut();
 		} else {
 			treeFilterBox.fadeIn();
+			treeFilterItem.focus();
 		}
 
 		toolbarItem.toggleClass('active');