fixing bug on default autocomplete-input validation mechanism

src/main/webapp/app/home/home.component.html

@@ -22,6 +22,7 @@
 				<span id="home-logged-message" *ngIf="account" jhiTranslate="home.logged.message"
 					[translateValues]="{ username: account.login }">You are logged in as user "{{account.login}}".</span>
 			</div>
+				<!--
 						<div class="d-inline-block my-3">
 							<mat-form-field>
 							  <mat-label>Your Contexts</mat-label>
@@ -31,8 +32,9 @@
 							    </mat-option>
 							  </mat-select>
 						</mat-form-field>
-
 						</div>
+				-->		
+						
 					<div>
 					<div class="d-inline-block my-3" ngbDropdown #myDrop="ngbDropdown" ></div>
 						

src/main/webapp/app/home/home.component.ts

@@ -22,6 +22,7 @@ import { IContextNode } from 'app/services/i-context-node';
 	styleUrls: ['./home.component.scss'],
 	providers: [ContextsLoaderService],
 })
+
 export class HomeComponent implements OnInit {
 	account: Account | null = null;
 	
@@ -31,8 +32,6 @@ export class HomeComponent implements OnInit {
   //public filteredContextsStr: Observable<string[]>| undefined;
   	chooseContextForm: FormGroup | any;
   	resType: string;
-  
-  
 	
 	constructor(
 		private accountService: AccountService, 
@@ -84,20 +83,41 @@ export class HomeComponent implements OnInit {
   
    
 	//PER VALIDAZIONE FORM
+	/*
 	  checkForErrorsIn(formControl: AbstractControl): string {
 	    if (formControl.hasError('required')) {
 	      return 'Value is required!';
 	    }
 	    return '';
 	  }
-	
+	  */
-	
+		  checkForErrorsIn(formControl: AbstractControl): string {
+	    if (formControl.hasError('')) {
+	      return 'Value is required!';
+	    }
+	    return '';
+	  }
+
+	// ValidationErrors | null =>!instanceOfContext(formControl?.value) ? { matchRequired: true } : null;
+
+
+
   displayFn(ctx: IContextNode): string {
     //return ctx.name ? ctx.name + ' | ' + ctx.id : '';
     return ctx.name;
   }
   
-  
+ 
+  instanceOfContextFn(context: any): context is IContextNode {
+	console.debug("*** In instanceOfContext: typeof_context: "+typeof context);
+    return !!context // truthy
+    && typeof context !== 'string' // Not just string input in the autocomplete
+    && 'name' in context; // Has some qualifying property of context type
+}
+
+
+
+
 /*
   displayFn(ctx: string): string {
     const tmp = ctx ? ctx + ' (poi ci va id) ': '';
@@ -105,6 +125,8 @@ export class HomeComponent implements OnInit {
     return tmp;
   }
 */
+
+/*
 	getContexts(): string[] {
 		if (this.account != null && this.account.resourceAccessDTO != null) {
 			// eslint-disable-next-line no-console
@@ -120,6 +142,8 @@ export class HomeComponent implements OnInit {
 			return [];
 		}
 	}
+*/
+
 
   copyUid(val: any): void {
     if (val instanceof FormControl) {