demo: update menu sider demo

components/menu/demo/sider.md

@@ -19,31 +19,24 @@ const SubMenu = Menu.SubMenu;
 const MenuItemGroup = Menu.ItemGroup;
 
 const Sider = React.createClass({
-  getInitialState() {
-    return {
-      current: '1',
-    };
-  },
   handleClick(e) {
     console.log('click ', e);
-    this.setState({
-      current: e.key,
-    });
   },
   render() {
     return (
-      <Menu onClick={this.handleClick}
+      <Menu
+        onClick={this.handleClick}
         style={{ width: 240 }}
+        defaultSelectedKeys={['1']}
         defaultOpenKeys={['sub1']}
-        selectedKeys={[this.state.current]}
         mode="inline"
       >
         <SubMenu key="sub1" title={<span><Icon type="mail" /><span>Navigation One</span></span>}>
-          <MenuItemGroup title="Item 1">
+          <MenuItemGroup key="g1" title="Item 1">
             <Menu.Item key="1">Option 1</Menu.Item>
             <Menu.Item key="2">Option 2</Menu.Item>
           </MenuItemGroup>
-          <MenuItemGroup title="Item 2">
+          <MenuItemGroup key="g2" title="Item 2">
             <Menu.Item key="3">Option 3</Menu.Item>
             <Menu.Item key="4">Option 4</Menu.Item>
           </MenuItemGroup>
@@ -66,5 +59,6 @@ const Sider = React.createClass({
     );
   },
 });
+
 ReactDOM.render(<Sider />, mountNode);
 ````

components/style/core/motion.less

@@ -10,6 +10,6 @@
 .ant-motion-collapse {
   overflow: hidden;
   &-active {
-    transition: height .2s @ease-out;
+    transition: height .2s ease-out;
   }
 }