steps to reproduce

1. load the attached zul
2. type ch in the textbox

current result

ZK moves the focus to Tree, so that users can't continue his typing

debug info

• when opening a treeitem, treeitem's setopen() enforce moving focus on its parent tree.

  zul.sel.Treeitem = zk.$extends(zul.sel.ItemWidget, {
  	_open: true,
  	$define: {
  		
  		
  		open: function (open, fromServer) {
                      ....
                     tree.focus();
                  }
  

  we can consider not moving the focus.

• Maybe there is another use case that requires getting focus while opening, e.g. a user opens a treeitem by mouse clicking instead of API. Then we can differentiate 2 cases with fromServer flag.

workaround

		
		zk.afterLoad('zul.sel', function() {
		    var oldMethods = {};
		    zk.override(zul.sel.Treeitem.prototype, oldMethods, {
				setOpen: function (open, fromServer) {
					var previouslyFocused = zk.Widget.$(jq(':focus'));
					oldMethods.setOpen.apply(this, arguments);
					if (previouslyFocused){
					    previouslyFocused.focus();
                                       }
				}		
		    });
		});

debug info

• moving focus is a general issue that we will face when implementing every widget. We should collect use cases and conclude a design rule
• it's better to focus a tree in doClick (click event handler) instead of setOpen()