diff --git a/src/vs/workbench/browser/parts/compositeBar.ts b/src/vs/workbench/browser/parts/compositeBar.ts
index f41f817cdc59f3184a611439730e0c970fad7423..cc17d550bed12dbd4f863a7578917aa3cb24f1a8 100644
--- a/src/vs/workbench/browser/parts/compositeBar.ts
+++ b/src/vs/workbench/browser/parts/compositeBar.ts
@@ -304,6 +304,10 @@ export class CompositeBar extends Widget implements ICompositeBar {
 		}
 	}
 
+	recomputeSizes(): void {
+		this.computeSizes(this.model.visibleItems);
+	}
+
 	layout(dimension: Dimension): void {
 		this.dimension = dimension;
 		if (dimension.height === 0 || dimension.width === 0) {
diff --git a/src/vs/workbench/browser/parts/panel/panelPart.ts b/src/vs/workbench/browser/parts/panel/panelPart.ts
index 632083397e7d1023d7d329ac66a63bf4503e3c98..6a221b35e7c97774be76aac92020b9ae4674b1d2 100644
--- a/src/vs/workbench/browser/parts/panel/panelPart.ts
+++ b/src/vs/workbench/browser/parts/panel/panelPart.ts
@@ -294,6 +294,10 @@ export abstract class BasePanelPart extends CompositePart<PaneComposite> impleme
 			pinnedAction.setActivity(activity);
 		}
 
+		// Composite Bar Swither needs to refresh tabs sizes and overflow action
+		this.compositeBar.recomputeSizes();
+		this.layoutCompositeBar();
+
 		// only update our cached panel info after extensions are done registering
 		if (this.extensionsRegistered) {
 			this.saveCachedPanels();