Hide the contributed viewlet if no views are registered

src/vs/workbench/api/browser/activitybarExtensionPoint.ts

@@ -91,7 +91,7 @@ activityGroupExtensionPoint.setHandler((extensions) => {
 			const id = `workbench.view.extension.${descriptor.id}`;
 			const title = descriptor.title;
 			const cssClass = `extensionViewlet-${descriptor.id}`;
-			const location: ViewLocation = ViewLocation.register(id);
+			const location: ViewLocation = ViewLocation.register(id, true);
 
 			// Generate CSS to show the icon in the activity bar
 			const iconClass = `.monaco-workbench > .activitybar .monaco-action-bar .action-label.${cssClass}`;

src/vs/workbench/browser/parts/activitybar/activitybarPart.ts

@@ -33,6 +33,8 @@ import { isMacintosh } from 'vs/base/common/platform';
 import { ILifecycleService, LifecyclePhase } from 'vs/platform/lifecycle/common/lifecycle';
 import { Dimension, scheduleAtNextAnimationFrame } from 'vs/base/browser/dom';
 import { Color } from 'vs/base/common/color';
+import { ViewLocation, ViewsRegistry } from 'vs/workbench/common/views';
+import { ViewletDescriptor } from 'vs/workbench/browser/viewlet';
 
 export class ActivitybarPart extends Part {
 
@@ -83,11 +85,14 @@ export class ActivitybarPart extends Part {
 		});
 
 		this.registerListeners();
+		this.updateCompositebar();
 	}
 
 	private registerListeners(): void {
 
-		this.toUnbind.push(this.viewletService.onDidViewletRegister(viewletDescriptor => this.compositeBar.addComposite(viewletDescriptor, false)));
+		this.toUnbind.push(this.viewletService.onDidViewletRegister(() => this.updateCompositebar()));
+		this.toUnbind.push(ViewsRegistry.onViewsRegistered(() => this.updateCompositebar()));
+		this.toUnbind.push(ViewsRegistry.onViewsDeregistered(() => this.updateCompositebar()));
 
 		// Activate viewlet action on opening of a viewlet
 		this.toUnbind.push(this.viewletService.onDidViewletOpen(viewlet => this.compositeBar.activateComposite(viewlet.getId())));
@@ -183,7 +188,9 @@ export class ActivitybarPart extends Part {
 	private showContextMenu(e: MouseEvent): void {
 		const event = new StandardMouseEvent(e);
 
-		const actions: Action[] = this.viewletService.getViewlets().map(viewlet => this.instantiationService.createInstance(ToggleCompositePinnedAction, viewlet, this.compositeBar));
+		const actions: Action[] = this.viewletService.getViewlets()
+			.filter(viewlet => this.canShow(viewlet))
+			.map(viewlet => this.instantiationService.createInstance(ToggleCompositePinnedAction, viewlet, this.compositeBar));
 		actions.push(new Separator());
 		actions.push(this.instantiationService.createInstance(ToggleActivityBarVisibilityAction, ToggleActivityBarVisibilityAction.ID, nls.localize('hideActivitBar', "Hide Activity Bar")));
 
@@ -215,6 +222,26 @@ export class ActivitybarPart extends Part {
 		});
 	}
 
+	private updateCompositebar(): void {
+		const viewlets = this.viewletService.getViewlets();
+		for (const viewlet of viewlets) {
+			const canShow = this.canShow(viewlet);
+			if (canShow) {
+				this.compositeBar.addComposite(viewlet, false);
+			} else {
+				this.compositeBar.removeComposite(viewlet.id);
+			}
+		}
+	}
+
+	private canShow(viewlet: ViewletDescriptor): boolean {
+		const viewLocation = ViewLocation.get(viewlet.id);
+		if (viewLocation && viewLocation.contributed) {
+			return ViewsRegistry.getViews(viewLocation).length > 0;
+		}
+		return true;
+	}
+
 	public getPinned(): string[] {
 		return this.viewletService.getViewlets().map(v => v.id).filter(id => this.compositeBar.isPinned(id));
 	}

src/vs/workbench/common/views.ts

@@ -18,8 +18,8 @@ import { ThemeIcon } from 'vs/platform/theme/common/themeService';
 export class ViewLocation {
 
 	private static locations: Map<string, ViewLocation> = new Map<string, ViewLocation>();
-	static register(id: string): ViewLocation {
-		const viewLocation = new ViewLocation(id);
+	static register(id: string, contributed: boolean): ViewLocation {
+		const viewLocation = new ViewLocation(id, contributed);
 		ViewLocation.locations.set(id, viewLocation);
 		return viewLocation;
 	}
@@ -27,12 +27,13 @@ export class ViewLocation {
 		return ViewLocation.locations.get(value);
 	}
 
-	static readonly Explorer: ViewLocation = ViewLocation.register('workbench.view.explorer');
-	static readonly Debug: ViewLocation = ViewLocation.register('workbench.view.debug');
-	static readonly Extensions: ViewLocation = ViewLocation.register('workbench.view.extensions');
+	static readonly Explorer: ViewLocation = ViewLocation.register('workbench.view.explorer', false);
+	static readonly Debug: ViewLocation = ViewLocation.register('workbench.view.debug', false);
+	static readonly Extensions: ViewLocation = ViewLocation.register('workbench.view.extensions', false);
 
-	private constructor(private _id: string) { }
+	private constructor(private _id: string, private _contributed: boolean) { }
 	get id(): string { return this._id; }
+	get contributed(): boolean { return this._contributed; }
 
 }