diff --git a/src/vs/platform/quickOpen/common/quickOpen.ts b/src/vs/platform/quickOpen/common/quickOpen.ts
index a6a169303b9715bc2169340cc9a02166f0fa2e1b..eef2fa91bd5f718d4789b9b611d2e59746e0febe 100644
--- a/src/vs/platform/quickOpen/common/quickOpen.ts
+++ b/src/vs/platform/quickOpen/common/quickOpen.ts
@@ -86,6 +86,9 @@ export interface IPickOptions {
 	 */
 	contextKey?: string;
 
+	/**
+	 * an optional flag to make this picker multi-select (honoured by extension API)
+	 */
 	multiSelect?: boolean;
 }
 
diff --git a/src/vs/vscode.d.ts b/src/vs/vscode.d.ts
index 0db6fc8d414c787378f83cb12a5872e4fd8ea75c..2295b78cdc197e4d90e6cf01e26ce8814d55c0a5 100644
--- a/src/vs/vscode.d.ts
+++ b/src/vs/vscode.d.ts
@@ -1554,6 +1554,9 @@ declare module 'vscode' {
 		 */
 		ignoreFocusOut?: boolean;
 
+		/**
+		 * An optional flag to make the picker multi-select, if true the result is an array of picks.
+		 */
 		multiSelect?: boolean;
 
 		/**
@@ -1562,10 +1565,16 @@ declare module 'vscode' {
 		onDidSelectItem?(item: QuickPickItem | string): any;
 	}
 
+	/**
+	 * Represents an item that can be selected in a multi-select quick pick UI.
+	 */
 	export interface MultiSelectQuickPickItem extends QuickPickItem {
 		selected?: boolean;
 	}
 
+	/**
+	 * Options to configure the behavior of the multi-select quick pick UI. (Marker type.)
+	 */
 	export interface MultiSelectQuickPickOptions extends QuickPickOptions {
 		multiSelect: true;
 	}
@@ -5077,7 +5086,7 @@ declare module 'vscode' {
 		 * @param items An array of strings, or a promise that resolves to an array of strings.
 		 * @param options Configures the behavior of the selection list.
 		 * @param token A token that can be used to signal cancellation.
-		 * @return A promise that resolves to the selection or `undefined`.
+		 * @return A promise that resolves to the selected item(s) or `undefined`.
 		 */
 		export function showQuickPick(items: string[] | Thenable<string[]>, options: MultiSelectQuickPickOptions, token?: CancellationToken): Thenable<string[] | undefined>;
 		export function showQuickPick(items: string[] | Thenable<string[]>, options?: QuickPickOptions, token?: CancellationToken): Thenable<string | undefined>;
@@ -5088,7 +5097,7 @@ declare module 'vscode' {
 		 * @param items An array of items, or a promise that resolves to an array of items.
 		 * @param options Configures the behavior of the selection list.
 		 * @param token A token that can be used to signal cancellation.
-		 * @return A promise that resolves to the selected item or `undefined`.
+		 * @return A promise that resolves to the selected item(s) or `undefined`.
 		 */
 		export function showQuickPick<T extends MultiSelectQuickPickItem>(items: T[] | Thenable<T[]>, options: MultiSelectQuickPickOptions, token?: CancellationToken): Thenable<T[] | undefined>;
 		export function showQuickPick<T extends QuickPickItem>(items: T[] | Thenable<T[]>, options?: QuickPickOptions, token?: CancellationToken): Thenable<T | undefined>;
diff --git a/src/vs/workbench/browser/parts/quickinput/quickInput.ts b/src/vs/workbench/browser/parts/quickinput/quickInput.ts
index 182ca41f98647e8fcb0a4c7aa29171c8bbbd6238..be6f2ff0d33044cc5b5837ea34f464b7d56c460d 100644
--- a/src/vs/workbench/browser/parts/quickinput/quickInput.ts
+++ b/src/vs/workbench/browser/parts/quickinput/quickInput.ts
@@ -143,9 +143,11 @@ export class QuickInputService extends Component implements IQuickInputService {
 			this.resolve();
 		}
 
+		// TODO: Listen on cancellation token.
+
 		this.inputBox.setValue('');
 		// TODO: Localize shortcut.
-		this.inputBox.setPlaceholder(options.placeHolder ? localize('quickInput.ctrlSpaceToSelectWithPlaceholder', "{1} ({0} to toggle)", 'Cmd+Space', options.placeHolder) : localize('quickInput.ctrlSpaceToSelect', "{0} to toggle", 'Cmd+Space'));
+		this.inputBox.setPlaceholder(options.placeHolder ? localize('quickInput.ctrlSpaceToSelectWithPlaceholder', "{1} ({0} to toggle)", 'Ctrl+Space', options.placeHolder) : localize('quickInput.ctrlSpaceToSelect', "{0} to toggle", 'Ctrl+Space'));
 		// TODO: Progress indication.
 		this.checkboxList.setElements(await picks);