diff --git a/src/vs/platform/actionWidget/browser/actionList.ts b/src/vs/platform/actionWidget/browser/actionList.ts
index 2ffd94bf18d..069d3dd85bf 100644
--- a/src/vs/platform/actionWidget/browser/actionList.ts
+++ b/src/vs/platform/actionWidget/browser/actionList.ts
@@ -252,6 +252,14 @@ class ActionItemRenderer<T> implements IListRenderer<IActionListItem<T>, IAction
 
 		dom.setVisibility(!element.hideIcon, data.icon);
 
+		// Set aria-expanded for section toggle items
+		if (element.isSectionToggle) {
+			const expanded = element.group?.icon === Codicon.chevronDown;
+			data.container.setAttribute('aria-expanded', String(expanded));
+		} else {
+			data.container.removeAttribute('aria-expanded');
+		}
+
 		// Apply optional className - clean up previous to avoid stale classes
 		// from virtualized row reuse
 		if (data.previousClassName) {
@@ -1109,8 +1117,12 @@ export class ActionListWidget<T> extends Disposable {
 		}
 
 		const element = e.elements[0];
-		if (element.isSectionToggle) {
+		if (element.isSectionToggle && element.section) {
 			this._list.setSelection([]);
+			const section = element.section;
+			queueMicrotask(() => {
+				this._toggleSection(section);
+			});
 			return;
 		}
 		// Don't select when clicking the toolbar or submenu indicator
@@ -1444,11 +1456,6 @@ export class ActionListWidget<T> extends Disposable {
 	}
 
 	private onListClick(e: IListMouseEvent<IActionListItem<T>>): void {
-		if (e.element && e.element.isSectionToggle && e.element.section) {
-			const section = e.element.section;
-			queueMicrotask(() => this._toggleSection(section));
-			return;
-		}
 		if (e.element && this.focusCondition(e.element)) {
 			this._list.setFocus([]);
 		}
diff --git a/src/vs/workbench/contrib/chat/browser/widget/input/chatModelPicker.ts b/src/vs/workbench/contrib/chat/browser/widget/input/chatModelPicker.ts
index 415ba99cdce..242f98e8dd3 100644
--- a/src/vs/workbench/contrib/chat/browser/widget/input/chatModelPicker.ts
+++ b/src/vs/workbench/contrib/chat/browser/widget/input/chatModelPicker.ts
@@ -447,9 +447,15 @@ export function buildModelPickerItems(
 export function getModelPickerAccessibilityProvider() {
 	return {
 		isChecked(element: IActionListItem<IActionWidgetDropdownAction>) {
+			if (element.isSectionToggle) {
+				return undefined;
+			}
 			return element.kind === ActionListItemKind.Action ? !!element?.item?.checked : undefined;
 		},
 		getRole: (element: IActionListItem<IActionWidgetDropdownAction>) => {
+			if (element.isSectionToggle) {
+				return 'menuitem';
+			}
 			switch (element.kind) {
 				case ActionListItemKind.Action: return 'menuitemradio';
 				case ActionListItemKind.Separator: return 'separator';