title: Angular 4 reactive form is not clearing the validations after resetting the form
body: <p>I am using Angular 4.4.6 reactive form with Angular Material 2.0.0-beta.12 in my application. This is my component,</p>
  
  <pre><code>import { Component, OnInit } from '@angular/core';
  import { FormGroup, FormControl, Validators } from '@angular/forms';
  
  @Component({
      selector: 'app-quick-file',
      templateUrl: './quick-file.component.html',
      styleUrls: ['./quick-file.component.css']
  })
  export class QuickFileComponent implements OnInit {
  
      quickFileForm: FormGroup;
  
  
      constructor() { }
  
      ngOnInit() {
          this.initQuickFileForm();
      }
  
      private initQuickFileForm () {
          this.quickFileForm = new FormGroup({
              'fileOpenDate': new FormControl(new Date(), Validators.required),
              'fileSubjectEn': new FormControl(null, Validators.required),
              'categoryId': new FormControl(null, Validators.required),
              'subCategoryId': new FormControl(null),
              'primaryClientId': new FormControl(null, Validators.required),
              'primaryConsultantId': new FormControl(null, Validators.required)
          });
      }
  
      saveQuickFileForm() {
          console.log(this.quickFileForm);
          this.quickFileForm.reset();
      }
  
  }
  </code></pre>
  
  <p>Here is my template,</p>
  
  <pre><code>&lt;div&gt;
      &lt;form [formGroup]="quickFileForm" (ngSubmit)="saveQuickFileForm()"&gt;
          &lt;mat-form-field class="common-form-field"&gt;
              &lt;input matInput [matDatepicker]="openDatePicker" formControlName="fileOpenDate" placeholder="Choose Date"&gt;
              &lt;mat-datepicker-toggle matSuffix [for]="openDatePicker"&gt;&lt;/mat-datepicker-toggle&gt;
              &lt;mat-datepicker #openDatePicker&gt;&lt;/mat-datepicker&gt;
          &lt;/mat-form-field&gt;
  
          &lt;mat-form-field class="common-form-field"&gt;
              &lt;input type="text" matInput formControlName="fileSubjectEn" placeholder="Subject in English"&gt;
          &lt;/mat-form-field&gt;
  
          &lt;mat-form-field class="common-form-field"&gt;
              &lt;mat-select formControlName="categoryId" placeholder="Choose category"&gt;
                  &lt;mat-option value="1"&gt;opt 1&lt;/mat-option&gt;
                  &lt;mat-option value="2"&gt;opt 2&lt;/mat-option&gt;
                  &lt;mat-option value="3"&gt;opt 3&lt;/mat-option&gt;
              &lt;/mat-select&gt;
          &lt;/mat-form-field&gt;
  
          &lt;mat-form-field class="common-form-field"&gt;
              &lt;mat-select formControlName="subCategoryId" placeholder="Choose subcategory"&gt;
                  &lt;mat-option value="1"&gt;opt 1&lt;/mat-option&gt;
                  &lt;mat-option value="2"&gt;opt 2&lt;/mat-option&gt;
                  &lt;mat-option value="3"&gt;opt 3&lt;/mat-option&gt;
              &lt;/mat-select&gt;
          &lt;/mat-form-field&gt;
  
          &lt;mat-form-field class="common-form-field"&gt;
              &lt;mat-select formControlName="primaryClientId" placeholder="Choose subcategory"&gt;
                  &lt;mat-option value="1"&gt;opt 1&lt;/mat-option&gt;
                  &lt;mat-option value="2"&gt;opt 2&lt;/mat-option&gt;
                  &lt;mat-option value="3"&gt;opt 3&lt;/mat-option&gt;
              &lt;/mat-select&gt;
          &lt;/mat-form-field&gt;
  
          &lt;mat-form-field class="common-form-field"&gt;
              &lt;mat-select formControlName="primaryConsultantId" placeholder="Choose subcategory"&gt;
                  &lt;mat-option value="1"&gt;opt 1&lt;/mat-option&gt;
                  &lt;mat-option value="2"&gt;opt 2&lt;/mat-option&gt;
                  &lt;mat-option value="3"&gt;opt 3&lt;/mat-option&gt;
              &lt;/mat-select&gt;
          &lt;/mat-form-field&gt;
      &lt;/form&gt;
  &lt;/div&gt;
  </code></pre>
  
  <p>Validation errors are showing even after I reset the form. I also tried the following methods.</p>
  
  <pre><code>this.quickFileForm.clearValidators();
  this.quickFileForm.markAsPristine();
  this.quickFileForm.markAsPristine();
  </code></pre>
  
  <p>What could be the error in my code and the possible solution? Thank you.</p>