list: do not set aria-selected for listbox roles

src/vs/base/browser/ui/list/listWidget.ts

@@ -182,17 +182,19 @@ class Trait<T> implements ISpliceable<boolean>, IDisposable {
 
 class SelectionTrait<T> extends Trait<T> {
 
-	constructor() {
+	constructor(private setAriaSelected: boolean) {
 		super('selected');
 	}
 
 	renderIndex(index: number, container: HTMLElement): void {
 		super.renderIndex(index, container);
 
-		if (this.contains(index)) {
-			container.setAttribute('aria-selected', 'true');
-		} else {
-			container.setAttribute('aria-selected', 'false');
+		if (this.setAriaSelected) {
+			if (this.contains(index)) {
+				container.setAttribute('aria-selected', 'true');
+			} else {
+				container.setAttribute('aria-selected', 'false');
+			}
 		}
 	}
 }
@@ -1198,7 +1200,7 @@ export class List<T> implements ISpliceable<T>, IDisposable {
 		renderers: IListRenderer<any /* TODO@joao */, any>[],
 		private _options: IListOptions<T> = DefaultOptions
 	) {
-		this.selection = new SelectionTrait();
+		this.selection = new SelectionTrait(this._options.ariaRole !== 'listbox');
 		this.focus = new Trait('focused');
 
 		mixin(_options, defaultStyles, false);