feat(select): Prevent header/footer click #5911

Author: IvayloG

Diff for: projects/igniteui-angular/src/lib/select/select.component.html

@@ -30,6 +30,7 @@
 
     <!-- Version 3 -->
     <div igxToggle class="igx-drop-down__list--select"
+    (mousedown)="mousedownHandler($event);"
     (onOpening)="onToggleOpening($event)" (onOpened)="onToggleOpened()"
     (onClosing)="onToggleClosing($event)" (onClosed)="onToggleClosed()">
         <ng-content *ngTemplateOutlet="headerTemplate">

Diff for: projects/igniteui-angular/src/lib/select/select.component.ts

@@ -453,5 +453,13 @@ export class IgxSelectComponent extends IgxDropDownComponent implements IgxSelec
             this._statusChanges$.unsubscribe();
         }
     }
+
+    /**
+     * @hidden @internal
+     * Prevent input blur - closing the items container on Header/Footer Template click.
+     */
+   public mousedownHandler(event) {
+        event.preventDefault();
+    }
 }