diff --git a/src/vs/workbench/browser/parts/sidebar/sidebarPart.ts b/src/vs/workbench/browser/parts/sidebar/sidebarPart.ts
index 7cdae2222f5..2c0e93b818a 100644
--- a/src/vs/workbench/browser/parts/sidebar/sidebarPart.ts
+++ b/src/vs/workbench/browser/parts/sidebar/sidebarPart.ts
@@ -161,7 +161,7 @@ export class SidebarPart extends AbstractPaneCompositePart {
 
 	protected getCompoisteBarOptions(): IPaneCompositeBarOptions {
 		return {
-			partContainerClass: 'activitybar',
+			partContainerClass: 'sidebar',
 			pinnedViewContainersKey: ActivitybarPart.pinnedViewContainersKey,
 			placeholderViewContainersKey: ActivitybarPart.placeholderViewContainersKey,
 			icon: true,