diff --git a/src/tsconfig.json b/src/tsconfig.json
index 25a1f449cc9..7fbb44c3ec5 100644
--- a/src/tsconfig.json
+++ b/src/tsconfig.json
@@ -9,7 +9,8 @@
 		"lib": [
 			"dom",
 			"es5",
-			"es2015.iterable"
+			"es2015.iterable",
+			"webworker"
 		]
 	},
 	"include": [
@@ -19,4 +20,4 @@
 	"exclude": [
 		"./typings/require-monaco.d.ts"
 	]
-}
\ No newline at end of file
+}
diff --git a/src/vs/code/electron-browser/issue/issueReporterMain.ts b/src/vs/code/electron-browser/issue/issueReporterMain.ts
index 2f9b372c20e..decce9a2e02 100644
--- a/src/vs/code/electron-browser/issue/issueReporterMain.ts
+++ b/src/vs/code/electron-browser/issue/issueReporterMain.ts
@@ -346,7 +346,7 @@ export class IssueReporter extends Disposable {
 		const showInfoElements = document.getElementsByClassName('showInfo');
 		for (let i = 0; i < showInfoElements.length; i++) {
 			const showInfo = showInfoElements.item(i);
-			showInfo!.addEventListener('click', (e) => {
+			showInfo!.addEventListener('click', (e: MouseEvent) => {
 				e.preventDefault();
 				const label = (<HTMLDivElement>e.target);
 				if (label) {
diff --git a/src/vs/workbench/contrib/welcome/walkThrough/browser/walkThroughPart.ts b/src/vs/workbench/contrib/welcome/walkThrough/browser/walkThroughPart.ts
index 2e85c4301fe..7bae52d70b7 100644
--- a/src/vs/workbench/contrib/welcome/walkThrough/browser/walkThroughPart.ts
+++ b/src/vs/workbench/contrib/welcome/walkThrough/browser/walkThroughPart.ts
@@ -129,7 +129,7 @@ export class WalkThroughPart extends BaseEditor {
 		this.disposables.add(this.addEventListener(this.content, 'blur', e => {
 			this.editorFocus.reset();
 		}));
-		this.disposables.add(this.addEventListener(this.content, 'focusin', e => {
+		this.disposables.add(this.addEventListener(this.content, 'focusin', (e: FocusEvent) => {
 			// Work around scrolling as side-effect of setting focus on the offscreen zone widget (#18929)
 			if (e.target instanceof HTMLElement && e.target.classList.contains('zone-widget-container')) {
 				const scrollPosition = this.scrollbar.getScrollPosition();