diff --git a/extensions/markdown-language-features/src/features/previewManager.ts b/extensions/markdown-language-features/src/features/previewManager.ts
index d18850b0f22..bffab3ac74b 100644
--- a/extensions/markdown-language-features/src/features/previewManager.ts
+++ b/extensions/markdown-language-features/src/features/previewManager.ts
@@ -147,13 +147,13 @@ export class MarkdownPreviewManager implements vscode.WebviewPanelSerializer {
 			}
 		});
 
-		preview.onDidChangeViewState(({ active }) => {
+		preview.onDidChangeViewState(({ webviewPanel }) => {
 			disposeAll(this.previews.filter(otherPreview => preview !== otherPreview && preview!.matches(otherPreview)));
 
 			vscode.commands.executeCommand('setContext', MarkdownPreviewManager.markdownPreviewActiveContextKey,
-				active);
+				webviewPanel.visible);
 
-			this.activePreview = active ? preview : undefined;
+			this.activePreview = webviewPanel.visible ? preview : undefined;
 		});
 
 		return preview;
diff --git a/src/vs/vscode.proposed.d.ts b/src/vs/vscode.proposed.d.ts
index 878b329df2d..2b0030d68c5 100644
--- a/src/vs/vscode.proposed.d.ts
+++ b/src/vs/vscode.proposed.d.ts
@@ -691,6 +691,11 @@ declare module 'vscode' {
 		 */
 		readonly viewColumn?: ViewColumn;
 
+		/**
+		 * Is the panel current visible?
+		 */
+		readonly visible: boolean;
+
 		/**
 		 * Fired when the panel's view state changes.
 		 */
@@ -724,9 +729,14 @@ declare module 'vscode' {
 		dispose(): any;
 	}
 
+	/**
+	 * Event fired when a webview panel's view state changes.
+	 */
 	export interface WebviewPanelOnDidChangeViewStateEvent {
-		readonly viewColumn: ViewColumn;
-		readonly active: boolean;
+		/**
+		 * Webview panel who's view state changed.
+		 */
+		readonly webviewPanel: WebviewPanel;
 	}
 
 	/**
diff --git a/src/vs/workbench/api/node/extHostWebview.ts b/src/vs/workbench/api/node/extHostWebview.ts
index f8bbc3f7961..0f9be6d7c77 100644
--- a/src/vs/workbench/api/node/extHostWebview.ts
+++ b/src/vs/workbench/api/node/extHostWebview.ts
@@ -97,7 +97,7 @@ export class ExtHostWebviewPanel implements vscode.WebviewPanel {
 	private readonly _proxy: MainThreadWebviewsShape;
 	private _isDisposed: boolean = false;
 	private _viewColumn: vscode.ViewColumn;
-	private _active: boolean;
+	private _visible: boolean;
 
 	public readonly onDisposeEmitter = new Emitter<void>();
 	public readonly onDidDispose: Event<void> = this.onDisposeEmitter.event;
@@ -155,9 +155,9 @@ export class ExtHostWebviewPanel implements vscode.WebviewPanel {
 		return this._viewColumn;
 	}
 
-	get active(): boolean {
+	get visible(): boolean {
 		this.assertNotDisposed();
-		return this._active;
+		return this._visible;
 	}
 
 	set viewColumn(value: vscode.ViewColumn) {
@@ -167,7 +167,7 @@ export class ExtHostWebviewPanel implements vscode.WebviewPanel {
 
 	set active(value: boolean) {
 		this.assertNotDisposed();
-		this._active = value;
+		this._visible = value;
 	}
 
 	public postMessage(message: any): Thenable<boolean> {
@@ -247,7 +247,7 @@ export class ExtHostWebviews implements ExtHostWebviewsShape {
 			if (panel.active !== active || panel.viewColumn !== viewColumn) {
 				panel.active = active;
 				panel.viewColumn = viewColumn;
-				panel.onDidChangeViewStateEmitter.fire({ active, viewColumn });
+				panel.onDidChangeViewStateEmitter.fire({ webviewPanel: panel });
 			}
 		}
 	}