diff --git a/examples/docs/en-US/form.md b/examples/docs/en-US/form.md
index 2035fbc88..8cdf621b0 100644
--- a/examples/docs/en-US/form.md
+++ b/examples/docs/en-US/form.md
@@ -283,7 +283,7 @@ It includes all kinds of input items, such as `input`, `select`, `radio` and `ch
   <el-form-item label="Activity form">
     <el-input type="textarea" v-model="form.desc"></el-input>
   </el-form-item>
-  <el-form-item label-width="120px">
+  <el-form-item>
     <el-button type="primary" @click="onSubmit">Create</el-button>
     <el-button>Cancel</el-button>
   </el-form-item>
@@ -445,7 +445,7 @@ Form component allows you to verify your data, helping you find and correct erro
   <el-form-item label="Activity form" prop="desc">
     <el-input type="textarea" v-model="ruleForm.desc"></el-input>
   </el-form-item>
-  <el-form-item label-width="120px">
+  <el-form-item>
     <el-button type="primary" @click="submitForm('ruleForm')">Create</el-button>
     <el-button @click="resetForm('ruleForm')">Reset</el-button>
   </el-form-item>
@@ -525,7 +525,7 @@ Form component allows you to verify your data, helping you find and correct erro
   <el-form-item label="Age" prop="age">
     <el-input v-model.number="ruleForm2.age"></el-input>
   </el-form-item>
-  <el-form-item label-width="120px">
+  <el-form-item>
     <el-button type="primary" @click="submitForm('ruleForm2')">Submit</el-button>
     <el-button @click="resetForm('ruleForm2')">Reset</el-button>
   </el-form-item>
@@ -634,7 +634,7 @@ Form component allows you to verify your data, helping you find and correct erro
   >
     <el-input v-model="domain.value"></el-input><el-button @click.prevent="removeDomain(domain)">Delete</el-button>
   </el-form-item>
-  <el-form-item label-width="120px">
+  <el-form-item>
     <el-button type="primary" @click="submitForm('dynamicValidateForm')">Submit</el-button>
     <el-button @click="addDomain">New domain</el-button>
     <el-button @click="resetForm('dynamicValidateForm')">Reset</el-button>
@@ -700,7 +700,7 @@ Form component allows you to verify your data, helping you find and correct erro
   >
     <el-input type="age" v-model.number="numberValidateForm.age" auto-complete="off"></el-input>
   </el-form-item>
-  <el-form-item label-width="100px">
+  <el-form-item>
     <el-button type="primary" @click="submitForm('numberValidateForm')">Submit</el-button>
     <el-button @click="resetForm('numberValidateForm')">Reset</el-button>
   </el-form-item>
@@ -735,7 +735,7 @@ Form component allows you to verify your data, helping you find and correct erro
 :::
 
 :::tip
-If an `el-form-item` has an empty `label`, and you wish to align it with other items, please add `label-width` on that `el-form-item`.
+When an `el-form-item` is nested in another `el-form-item`, its label width will be `0`. You can set `label-width` on that `el-form-item` if needed.
 :::
 
 ### Form Attributes
@@ -746,7 +746,7 @@ If an `el-form-item` has an empty `label`, and you wish to align it with other i
 | rules | validation rules of form | object | — | — |
 | inline | whether the form is inline | boolean | — | false |
 | label-position | position of label | string | left/right/top | right |
-| label-width | width of label, and all form items will inherit from `Form` | string | — | — |
+| label-width | width of label, and all its direct child form items will inherit this value | string | — | — |
 | label-suffix | suffix of the label | string | — | — |
 | show-message  | whether to show the error message | boolean | — | true |
 
diff --git a/examples/docs/zh-CN/form.md b/examples/docs/zh-CN/form.md
index 82d2a4c01..56970a540 100644
--- a/examples/docs/zh-CN/form.md
+++ b/examples/docs/zh-CN/form.md
@@ -277,7 +277,7 @@
   <el-form-item label="活动形式">
     <el-input type="textarea" v-model="form.desc"></el-input>
   </el-form-item>
-  <el-form-item label-width="80px">
+  <el-form-item>
     <el-button type="primary" @click="onSubmit">立即创建</el-button>
     <el-button>取消</el-button>
   </el-form-item>
@@ -436,7 +436,7 @@
   <el-form-item label="活动形式" prop="desc">
     <el-input type="textarea" v-model="ruleForm.desc"></el-input>
   </el-form-item>
-  <el-form-item label-width="100px">
+  <el-form-item>
     <el-button type="primary" @click="submitForm('ruleForm')">立即创建</el-button>
     <el-button @click="resetForm('ruleForm')">重置</el-button>
   </el-form-item>
@@ -515,7 +515,7 @@
   <el-form-item label="年龄" prop="age">
     <el-input v-model.number="ruleForm2.age"></el-input>
   </el-form-item>
-  <el-form-item label-width="100px">
+  <el-form-item>
     <el-button type="primary" @click="submitForm('ruleForm2')">提交</el-button>
     <el-button @click="resetForm('ruleForm2')">重置</el-button>
   </el-form-item>
@@ -623,7 +623,7 @@
   >
     <el-input v-model="domain.value"></el-input><el-button @click.prevent="removeDomain(domain)">删除</el-button>
   </el-form-item>
-  <el-form-item label-width="100px">
+  <el-form-item>
     <el-button type="primary" @click="submitForm('dynamicValidateForm')">提交</el-button>
     <el-button @click="addDomain">新增域名</el-button>
     <el-button @click="resetForm('dynamicValidateForm')">重置</el-button>
@@ -688,7 +688,7 @@
   >
     <el-input type="age" v-model.number="numberValidateForm.age" auto-complete="off"></el-input>
   </el-form-item>
-  <el-form-item label-width="100px">
+  <el-form-item>
     <el-button type="primary" @click="submitForm('numberValidateForm')">提交</el-button>
     <el-button @click="resetForm('numberValidateForm')">重置</el-button>
   </el-form-item>
@@ -723,7 +723,7 @@
 :::
 
 :::tip
-当 `el-form-item` 的 `label` 属性为空时，如果希望和其他 `label` 属性不为空的表单项内容对齐，请在 `el-form-item` 上设置 `label-width` 属性。
+嵌套在 `el-form-item` 中的 `el-form-item` 标签宽度默认为零，不会继承 `el-form` 的 `label-width`。如果需要可以为其单独设置 `label-width` 属性。
 :::
 
 ### Form Attributes
@@ -734,7 +734,7 @@
 | rules    | 表单验证规则 | object | — | — |
 | inline    | 行内表单模式 | boolean | — | false |
 | label-position | 表单域标签的位置 | string |  right/left/top            | right |
-| label-width | 表单域标签的宽度，所有的 form-item 都会继承 form 组件的 labelWidth 的值 | string | — | — |
+| label-width | 表单域标签的宽度，作为 Form 直接子元素的 form-item 会继承该值 | string | — | — |
 | label-suffix | 表单域标签的后缀 | string | — | — |
 | show-message  | 是否显示校验错误信息 | boolean | — | true |
 
diff --git a/examples/docs/zh-CN/menu.md b/examples/docs/zh-CN/menu.md
index 2e594b940..86697b689 100644
--- a/examples/docs/zh-CN/menu.md
+++ b/examples/docs/zh-CN/menu.md
@@ -190,7 +190,7 @@
   <el-radio-button :label="false">展开</el-radio-button>
   <el-radio-button :label="true">收起</el-radio-button>
 </el-radio-group>
-<el-menu default-active="2" class="el-menu-vertical-demo" @open="handleOpen" @close="handleClose" :collapse="isCollapse">
+<el-menu default-active="1-4-1" class="el-menu-vertical-demo" @open="handleOpen" @close="handleClose" :collapse="isCollapse">
   <el-submenu index="1">
     <template slot="title">
       <i class="el-icon-message"></i>
diff --git a/packages/form/src/form-item.vue b/packages/form/src/form-item.vue
index 6c7f201bf..5923765dc 100644
--- a/packages/form/src/form-item.vue
+++ b/packages/form/src/form-item.vue
@@ -87,7 +87,7 @@
         var ret = {};
         const label = this.label;
         if (this.form.labelPosition === 'top' || this.form.inline) return ret;
-        if (!label && !this.labelWidth) return ret;
+        if (!label && !this.labelWidth && this.isNested) return ret;
         var labelWidth = this.labelWidth || this.form.labelWidth;
         if (labelWidth) {
           ret.marginLeft = labelWidth;
@@ -95,9 +95,14 @@
         return ret;
       },
       form() {
-        var parent = this.$parent;
-        while (parent.$options.componentName !== 'ElForm') {
+        let parent = this.$parent;
+        let parentName = parent.$options.componentName;
+        while (parentName !== 'ElForm') {
+          if (parentName === 'ElFormItem') {
+            this.isNested = true;
+          }
           parent = parent.$parent;
+          parentName = parent.$options.componentName;
         }
         return parent;
       },
@@ -136,7 +141,8 @@
         validateState: '',
         validateMessage: '',
         validateDisabled: false,
-        validator: {}
+        validator: {},
+        isNested: false
       };
     },
     methods: {
diff --git a/packages/form/src/form.vue b/packages/form/src/form.vue
index 18d89b821..ab255a778 100644
--- a/packages/form/src/form.vue
+++ b/packages/form/src/form.vue
@@ -62,6 +62,10 @@
         });
       },
       validate(callback) {
+        if (!this.model) {
+          console.warn('[Element Warn][Form]model is required for validate to work!');
+          return;
+        };
         let valid = true;
         let count = 0;
         // 如果需要验证的fields为空，调用验证时立刻返回callback
diff --git a/packages/menu/src/menu.vue b/packages/menu/src/menu.vue
index d1ba47729..4993e1885 100644
--- a/packages/menu/src/menu.vue
+++ b/packages/menu/src/menu.vue
@@ -192,7 +192,7 @@
       initOpenedMenu() {
         const index = this.activedIndex;
         const activeItem = this.items[index];
-        if (!activeItem || this.mode === 'horizontal') return;
+        if (!activeItem || this.mode === 'horizontal' || this.collapse) return;
 
         let indexPath = activeItem.indexPath;
 
diff --git a/packages/popover/src/main.vue b/packages/popover/src/main.vue
index 6dbc3fde3..39e439aae 100644
--- a/packages/popover/src/main.vue
+++ b/packages/popover/src/main.vue
@@ -109,16 +109,17 @@ export default {
       this.showPopper = false;
     },
     handleMouseEnter() {
+      clearTimeout(this._timer);
       if (this.openDelay) {
-        setTimeout(() => {
+        this._timer = setTimeout(() => {
           this.showPopper = true;
         }, this.openDelay);
       } else {
         this.showPopper = true;
       }
-      clearTimeout(this._timer);
     },
     handleMouseLeave() {
+      clearTimeout(this._timer);
       this._timer = setTimeout(() => {
         this.showPopper = false;
       }, 200);
diff --git a/packages/tree/src/model/node.js b/packages/tree/src/model/node.js
index 99eb3f133..49461e55a 100644
--- a/packages/tree/src/model/node.js
+++ b/packages/tree/src/model/node.js
@@ -300,9 +300,9 @@ export default class Node {
   setChecked(value, deep, recursion, passValue) {
     this.indeterminate = value === 'half';
     this.checked = value === true;
-    let { allWithoutDisable } = getChildState(this.childNodes);
+    let { all, allWithoutDisable } = getChildState(this.childNodes);
 
-    if (this.childNodes.length && allWithoutDisable) {
+    if (this.childNodes.length && (!all && allWithoutDisable)) {
       this.checked = false;
       value = false;
     }
diff --git a/src/locale/lang/nl.js b/src/locale/lang/nl.js
index e8930268c..c4b929b36 100644
--- a/src/locale/lang/nl.js
+++ b/src/locale/lang/nl.js
@@ -16,7 +16,7 @@ export default {
       startTime: 'Starttijd',
       endDate: 'Einddatum',
       endTime: 'Eindtijd',
-      year: 'Jaar',
+      year: '',
       month1: 'januari',
       month2: 'februari',
       month3: 'maart',