Extjs4.2 下拉树 Ext.ux.TreePicker 的一个BUG修复。

这个下拉树在使用的时候滚动条不出现，原来只要在，代码中加入个

height:0,

var me = this,
            picker = new Ext.tree.Panel({
            shrinkWrapDock: 2,
            store: me.store,
            floating: true,
            displayField: me.displayField,
            columns: me.columns,
            minHeight: me.minPickerHeight,
            maxHeight: me.maxPickerHeight,
            height:0,
            rootVisible: me.rootVisible,
            manageHeight: false,
            listeners: {
                scope: me,
                itemclick: me.onItemClick
            },
            viewConfig: {
                listeners: {
                    scope: me,
                    render: me.onViewRender
                }
            }
        }),