fix overflow actions issue in panel/auxbar

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) {

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();