diff --git a/src/vs/vscode.d.ts b/src/vs/vscode.d.ts
index 7d8e42b70fc..f59aa3aa4fc 100644
--- a/src/vs/vscode.d.ts
+++ b/src/vs/vscode.d.ts
@@ -7912,7 +7912,7 @@ declare module 'vscode' {
 		 * @param options Options that control the dialog.
 		 * @returns A promise that resolves to the selected resources or `undefined`.
 		 */
-		export function showOpenDialog(options: OpenDialogOptions): Thenable<Uri[] | undefined>;
+		export function showOpenDialog(options?: OpenDialogOptions): Thenable<Uri[] | undefined>;
 
 		/**
 		 * Shows a file save dialog to the user which allows to select a file
@@ -7921,7 +7921,7 @@ declare module 'vscode' {
 		 * @param options Options that control the dialog.
 		 * @returns A promise that resolves to the selected resource or `undefined`.
 		 */
-		export function showSaveDialog(options: SaveDialogOptions): Thenable<Uri | undefined>;
+		export function showSaveDialog(options?: SaveDialogOptions): Thenable<Uri | undefined>;
 
 		/**
 		 * Opens an input box to ask the user for input.
diff --git a/src/vs/workbench/api/browser/mainThreadDialogs.ts b/src/vs/workbench/api/browser/mainThreadDialogs.ts
index 79c26c34570..ff3b66e935d 100644
--- a/src/vs/workbench/api/browser/mainThreadDialogs.ts
+++ b/src/vs/workbench/api/browser/mainThreadDialogs.ts
@@ -23,37 +23,37 @@ export class MainThreadDialogs implements MainThreadDiaglogsShape {
 		//
 	}
 
-	$showOpenDialog(options: MainThreadDialogOpenOptions): Promise<URI[] | undefined> {
+	$showOpenDialog(options?: MainThreadDialogOpenOptions): Promise<URI[] | undefined> {
 		return Promise.resolve(this._fileDialogService.showOpenDialog(MainThreadDialogs._convertOpenOptions(options)));
 	}
 
-	$showSaveDialog(options: MainThreadDialogSaveOptions): Promise<URI | undefined> {
+	$showSaveDialog(options?: MainThreadDialogSaveOptions): Promise<URI | undefined> {
 		return Promise.resolve(this._fileDialogService.showSaveDialog(MainThreadDialogs._convertSaveOptions(options)));
 	}
 
-	private static _convertOpenOptions(options: MainThreadDialogOpenOptions): IOpenDialogOptions {
+	private static _convertOpenOptions(options?: MainThreadDialogOpenOptions): IOpenDialogOptions {
 		const result: IOpenDialogOptions = {
-			openLabel: options.openLabel || undefined,
-			canSelectFiles: options.canSelectFiles || (!options.canSelectFiles && !options.canSelectFolders),
-			canSelectFolders: options.canSelectFolders,
-			canSelectMany: options.canSelectMany,
-			defaultUri: options.defaultUri ? URI.revive(options.defaultUri) : undefined,
-			title: options.title || undefined
+			openLabel: options?.openLabel || undefined,
+			canSelectFiles: options?.canSelectFiles || (!options?.canSelectFiles && !options?.canSelectFolders),
+			canSelectFolders: options?.canSelectFolders,
+			canSelectMany: options?.canSelectMany,
+			defaultUri: options?.defaultUri ? URI.revive(options.defaultUri) : undefined,
+			title: options?.title || undefined
 		};
-		if (options.filters) {
+		if (options?.filters) {
 			result.filters = [];
 			forEach(options.filters, entry => result.filters!.push({ name: entry.key, extensions: entry.value }));
 		}
 		return result;
 	}
 
-	private static _convertSaveOptions(options: MainThreadDialogSaveOptions): ISaveDialogOptions {
+	private static _convertSaveOptions(options?: MainThreadDialogSaveOptions): ISaveDialogOptions {
 		const result: ISaveDialogOptions = {
-			defaultUri: options.defaultUri ? URI.revive(options.defaultUri) : undefined,
-			saveLabel: options.saveLabel || undefined,
-			title: options.title || undefined
+			defaultUri: options?.defaultUri ? URI.revive(options.defaultUri) : undefined,
+			saveLabel: options?.saveLabel || undefined,
+			title: options?.title || undefined
 		};
-		if (options.filters) {
+		if (options?.filters) {
 			result.filters = [];
 			forEach(options.filters, entry => result.filters!.push({ name: entry.key, extensions: entry.value }));
 		}
diff --git a/src/vs/workbench/api/common/extHost.protocol.ts b/src/vs/workbench/api/common/extHost.protocol.ts
index eb3530c817c..6d21b5a745d 100644
--- a/src/vs/workbench/api/common/extHost.protocol.ts
+++ b/src/vs/workbench/api/common/extHost.protocol.ts
@@ -201,8 +201,8 @@ export interface MainThreadDialogSaveOptions {
 }
 
 export interface MainThreadDiaglogsShape extends IDisposable {
-	$showOpenDialog(options: MainThreadDialogOpenOptions): Promise<UriComponents[] | undefined>;
-	$showSaveDialog(options: MainThreadDialogSaveOptions): Promise<UriComponents | undefined>;
+	$showOpenDialog(options?: MainThreadDialogOpenOptions): Promise<UriComponents[] | undefined>;
+	$showSaveDialog(options?: MainThreadDialogSaveOptions): Promise<UriComponents | undefined>;
 }
 
 export interface MainThreadDecorationsShape extends IDisposable {
diff --git a/src/vs/workbench/api/common/extHostDialogs.ts b/src/vs/workbench/api/common/extHostDialogs.ts
index 393db6ff77a..69de2a3e7f8 100644
--- a/src/vs/workbench/api/common/extHostDialogs.ts
+++ b/src/vs/workbench/api/common/extHostDialogs.ts
@@ -15,13 +15,13 @@ export class ExtHostDialogs {
 		this._proxy = mainContext.getProxy(MainContext.MainThreadDialogs);
 	}
 
-	showOpenDialog(options: vscode.OpenDialogOptions): Promise<URI[] | undefined> {
+	showOpenDialog(options?: vscode.OpenDialogOptions): Promise<URI[] | undefined> {
 		return this._proxy.$showOpenDialog(options).then(filepaths => {
 			return filepaths ? filepaths.map(p => URI.revive(p)) : undefined;
 		});
 	}
 
-	showSaveDialog(options: vscode.SaveDialogOptions): Promise<URI | undefined> {
+	showSaveDialog(options?: vscode.SaveDialogOptions): Promise<URI | undefined> {
 		return this._proxy.$showSaveDialog(options).then(filepath => {
 			return filepath ? URI.revive(filepath) : undefined;
 		});