diff --git a/src/vs/base/common/async.ts b/src/vs/base/common/async.ts
index 53a7e38ee3cf391f894ca5cab6ee9f8ce09e547f..88d57b4307e99b95826f0746360f617944fd886a 100644
--- a/src/vs/base/common/async.ts
+++ b/src/vs/base/common/async.ts
@@ -442,13 +442,13 @@ export function sequence<T>(promiseFactories: ITask<Thenable<T>>[]): TPromise<T[
 	return TPromise.as(null).then(thenHandler);
 }
 
-export function first<T>(promiseFactories: ITask<TPromise<T>>[], shouldStop: (t: T) => boolean = t => !!t): TPromise<T> {
+export function first<T>(promiseFactories: ITask<TPromise<T>>[], shouldStop: (t: T) => boolean = t => !!t, defaultValue: T = null): TPromise<T> {
 	let index = 0;
 	const len = promiseFactories.length;
 
 	const loop: () => TPromise<T> = () => {
 		if (index >= len) {
-			return TPromise.as(null);
+			return TPromise.as(defaultValue);
 		}
 
 		const factory = promiseFactories[index++];
diff --git a/src/vs/platform/url/common/urlService.ts b/src/vs/platform/url/common/urlService.ts
index f4fbab19d7dc926b7acda24f878bb9e029bdcd4a..2d7fda8b99fc79354d8c53547946a1588915dd9d 100644
--- a/src/vs/platform/url/common/urlService.ts
+++ b/src/vs/platform/url/common/urlService.ts
@@ -9,6 +9,7 @@ import { IURLService, IURLHandler } from 'vs/platform/url/common/url';
 import URI from 'vs/base/common/uri';
 import { IDisposable, toDisposable } from 'vs/base/common/lifecycle';
 import { TPromise } from 'vs/base/common/winjs.base';
+import { first } from 'vs/base/common/async';
 
 declare module Array {
 	function from<T>(set: Set<T>): T[];
@@ -20,16 +21,9 @@ export class URLService implements IURLService {
 
 	private handlers = new Set<IURLHandler>();
 
-	async open(uri: URI): TPromise<boolean> {
+	open(uri: URI): TPromise<boolean> {
 		const handlers = Array.from(this.handlers);
-
-		for (const handler of handlers) {
-			if (await handler.handleURL(uri)) {
-				return true;
-			}
-		}
-
-		return false;
+		return first(handlers.map(h => () => h.handleURL(uri)), undefined, false);
 	}
 
 	registerHandler(handler: IURLHandler): IDisposable {
@@ -44,7 +38,7 @@ export class RelayURLService extends URLService implements IURLHandler {
 		super();
 	}
 
-	async open(uri: URI): TPromise<boolean> {
+	open(uri: URI): TPromise<boolean> {
 		return this.urlService.open(uri);
 	}
 
diff --git a/src/vs/workbench/parts/debug/browser/debugViewlet.ts b/src/vs/workbench/parts/debug/browser/debugViewlet.ts
index 2cc3d77ddf926227683c857a5732533efdc3d4a0..30ffc30d939529db426736e2841d36a02253b82d 100644
--- a/src/vs/workbench/parts/debug/browser/debugViewlet.ts
+++ b/src/vs/workbench/parts/debug/browser/debugViewlet.ts
@@ -66,10 +66,10 @@ export class DebugViewlet extends ViewContainerViewlet {
 		}));
 	}
 
-	async create(parent: HTMLElement): TPromise<void> {
-		await super.create(parent);
-
-		DOM.addClass(parent, 'debug-viewlet');
+	create(parent: HTMLElement): TPromise<void> {
+		return super.create(parent).then(() => {
+			DOM.addClass(parent, 'debug-viewlet');
+		});
 	}
 
 	public focus(): void {
diff --git a/src/vs/workbench/parts/files/electron-browser/explorerViewlet.ts b/src/vs/workbench/parts/files/electron-browser/explorerViewlet.ts
index 57326f164777509723c2b5c3961db0d1acbf1ce1..257e5d350824b5a70862474c7dfa87599c8eb795 100644
--- a/src/vs/workbench/parts/files/electron-browser/explorerViewlet.ts
+++ b/src/vs/workbench/parts/files/electron-browser/explorerViewlet.ts
@@ -173,10 +173,10 @@ export class ExplorerViewlet extends ViewContainerViewlet implements IExplorerVi
 		this._register(this.contextService.onDidChangeWorkspaceName(e => this.updateTitleArea()));
 	}
 
-	async create(parent: HTMLElement): TPromise<void> {
-		await super.create(parent);
-
-		DOM.addClass(parent, 'explorer-viewlet');
+	create(parent: HTMLElement): TPromise<void> {
+		return super.create(parent).then(() => {
+			DOM.addClass(parent, 'explorer-viewlet');
+		});
 	}
 
 	protected createView(viewDescriptor: IViewDescriptor, options: IViewletViewOptions): ViewletPanel {
diff --git a/src/vs/workbench/parts/update/electron-browser/releaseNotesEditor.ts b/src/vs/workbench/parts/update/electron-browser/releaseNotesEditor.ts
index f1dcc32c086e0e516f5ce4d907200f95e09c4b64..c32bfc0d3c4dc9b9130f72a90ac524af0b2e9be0 100644
--- a/src/vs/workbench/parts/update/electron-browser/releaseNotesEditor.ts
+++ b/src/vs/workbench/parts/update/electron-browser/releaseNotesEditor.ts
@@ -160,7 +160,7 @@ export class ReleaseNotesManager {
 		return body;
 	}
 
-	private async renderContent(text: string): TPromise<string> {
+	private async renderContent(text: string): Promise<string> {
 		const renderer = await this.getRenderer(text);
 		return marked(text, { renderer });
 	}
diff --git a/src/vs/workbench/parts/url/electron-browser/url.contribution.ts b/src/vs/workbench/parts/url/electron-browser/url.contribution.ts
index bc6c1f8faa39ed1be5140e3670afc15e8d1da9fc..375cfdad0a434a6614b9810df842a20472346445 100644
--- a/src/vs/workbench/parts/url/electron-browser/url.contribution.ts
+++ b/src/vs/workbench/parts/url/electron-browser/url.contribution.ts
@@ -27,11 +27,11 @@ export class OpenUrlAction extends Action {
 		super(id, label);
 	}
 
-	async run(): TPromise<any> {
-		const input = await this.quickInputService.input({ prompt: 'URL to open' });
-		const uri = URI.parse(input);
-
-		this.urlService.open(uri);
+	run(): TPromise<any> {
+		return this.quickInputService.input({ prompt: 'URL to open' }).then(input => {
+			const uri = URI.parse(input);
+			this.urlService.open(uri);
+		});
 	}
 }