title: ngx-mat-select-search doesn't works
body: <p>I wanted to implement ngx-mat-select-search in a form I use, but unfortunately, it doesn't works (I can't open the dropdown - it doesn't show me any value).</p>
  
  <p>My html:</p>
  
  <pre><code>&lt;div class="form"&gt;
    &lt;mat-form-field&gt;
      &lt;mat-select placeholder="Kunde" name="customer" #customer="ngModel" [(ngModel)]="currentCustomer"
        (ngModelChange)="dofilterCustomer()"&gt;
        &lt;ngx-mat-select-search&gt;&lt;/ngx-mat-select-search&gt;
        &lt;mat-option *ngFor="let customer of customers | async" [value]="customer"&gt;
          {{customer}}
        &lt;/mat-option&gt;
      &lt;/mat-select&gt;
    &lt;/mat-form-field&gt;
  &lt;/div&gt;
  </code></pre>
  
  <p>My .ts file:</p>
  
  <pre><code>import { Component, Inject, OnInit, ViewChild } from "@angular/core";
  import {
    MAT_DIALOG_DATA,
    MatDialogRef,
    MatDialogModule,
    MatSelect
  } from "@angular/material";
  import { TableService } from "../table.service";
  import { FormControl, Validators } from "@angular/forms";
  import { EntryDTO, Customer } from "../../models";
  import { SecurityService } from "src/app/security/security.service";
  import { MatAutocompleteModule } from "@angular/material/autocomplete";
  import { Observable } from "rxjs";
  import { map, startWith } from "rxjs/operators";
  
  @Component({
    selector: "app-add-dialog",
    templateUrl: "./add-dialog.component.html",
    styleUrls: ["./add-dialog.component.css"]
  })
  export class AddDialogComponent implements OnInit {
    constructor(
      public dialogRef: MatDialogRef&lt;AddDialogComponent&gt;,
      @Inject(MAT_DIALOG_DATA) public data: EntryDTO,
      public dataService: TableService
    ) {}
  
    customers!: Observable&lt;string[]&gt;;
    currentCustomer = "";
    forwarders!: Observable&lt;string[]&gt;;
    currentForwarder = "";
    bins!: Observable&lt;string[]&gt;;
    currentBin = "";
  
    @ViewChild("singleSelect") singleSelect!: MatSelect;
  
    ngOnInit() {}
  
    dofilterCustomer() {
      this.customers = this.dataService
        .getAllCustomers()
        .pipe(map(customers =&gt; this.filter(customers, this.currentCustomer)));
    }
  
    dofilterForwarder() {
      this.forwarders = this.dataService
        .getAllForwarders()
        .pipe(map(forwarders =&gt; this.filter(forwarders, this.currentForwarder)));
    }
  
    dofilterBins() {
      this.bins = this.dataService
        .getAllBins()
        .pipe(map(bins =&gt; this.filter(bins, this.currentBin)));
    }
  
    formControl = new FormControl("", [
      Validators.required
      // Validators.email,
    ]);
  
    getErrorMessage() {
      return this.formControl.hasError("required")
        ? "Required field"
        : this.formControl.hasError("email")
        ? "Not a valid email"
        : "";
    }
  
    submit() {
      this.dataService.addEntry(this.data);
    }
  
    onNoClick(): void {
      this.dialogRef.close();
    }
  
    public confirmAdd(): void {
      this.dataService.addEntry(this.data);
    }
  
    filter(values: string[], current: string) {
      return values.filter(value =&gt; value.toLowerCase().includes(current));
    }
  }
  </code></pre>
  
  <p>Initially I had the following code in my html. Then it worked, but i had no dropdown, just an "autocomplete-list":</p>
  
  <pre><code>&lt;div class="form"&gt;
    &lt;mat-form-field class="example-full-width accent"&gt;
      &lt;input type="text" #input placeholder="Kunde" aria-label="Number" name="customer" #customer="ngModel" matInput
        [(ngModel)]="currentCustomer" (ngModelChange)="dofilterCustomer()" [matAutocomplete]="auto1" required&gt;
      &lt;mat-error *ngIf="formControl.invalid"&gt;{{getErrorMessage()}}&lt;/mat-error&gt;
      &lt;mat-autocomplete #auto1="matAutocomplete"&gt;
        &lt;mat-option *ngFor="let customer of customers | async" [value]="customer"&gt;
          {{customer}}
        &lt;/mat-option&gt;
      &lt;/mat-autocomplete&gt;
    &lt;/mat-form-field&gt;
  &lt;/div&gt;
  </code></pre>
  
  <p>Maybe anybody could see what i am doing wrong ?</p>
  
  <p>Thank you in advance.</p>