fix selected state of select boxes (#19743)

* fix the selected state

* add comments

* validate parameters

src/sql/base/browser/ui/editableDropdown/browser/dropdown.ts

@@ -315,6 +315,8 @@ export class Dropdown extends Disposable implements IListVirtualDelegate<string>
 
 	private _updateDropDownList(): void {
 		this._selectList.splice(0, this._selectList.length, this._dataSource.filteredValues.map(v => { return { text: v }; }));
+		const selectedIndex = this._dataSource.filteredValues.indexOf(this.value);
+		this._selectList.setSelection(selectedIndex !== -1 ? [selectedIndex] : []);
 
 		let width = this._inputContainer.clientWidth;
 

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

@@ -1279,7 +1279,8 @@ export class List<T> implements ISpliceable<T>, IThemable, IDisposable {
 		private _options: IListOptions<T> = DefaultOptions
 	) {
 		const role = this._options.accessibilityProvider && this._options.accessibilityProvider.getWidgetRole ? this._options.accessibilityProvider?.getWidgetRole() : 'list';
-		this.selection = new SelectionTrait(role !== 'listbox');
+		// {{SQL CARBON EDIT}} - Change the parameter from 'role !== listbox' to 'role !== list', according to the doc https://www.w3.org/WAI/PF/HTML/wiki/RoleAttribute, list role is non-interactive.
+		this.selection = new SelectionTrait(role !== 'list');
 
 		mixin(_options, defaultStyles, false);
 

src/vs/base/browser/ui/selectBox/selectBoxCustom.ts

@@ -271,6 +271,7 @@ export class SelectBoxList extends Disposable implements ISelectBoxDelegate, ILi
 		// Populate select list for non-native select mode
 		if (this.selectList) {
 			this.selectList.splice(0, this.selectList.length, this.options);
+			this.selectList?.setSelection(this.selected !== -1 ? [this.selected] : []); // {{SQL CARBON EDIT}} - Set the selected indexes.
 		}
 	}