diff --git a/src/webviews/apps/shared/appBase.ts b/src/webviews/apps/shared/appBase.ts
index 737c1a6..ef143b4 100644
--- a/src/webviews/apps/shared/appBase.ts
+++ b/src/webviews/apps/shared/appBase.ts
@@ -89,31 +89,33 @@ export abstract class App<State = undefined> {
 		const id = nextIpcId();
 		this.log(`${this.appName}.sendCommand(${id}): name=${command.method}`);
 
-		return this.postMessage({ id: id, method: command.method, params: params });
+		this.postMessage({ id: id, method: command.method, params: params });
 	}
 
-	protected sendCommandWithCompletion<
+	protected async sendCommandWithCompletion<
 		TCommand extends IpcCommandType<any>,
-		TCompletion extends IpcNotificationType<{ completionId: string }>,
+		TCompletion extends IpcNotificationType<any>,
 	>(
 		command: TCommand,
 		params: IpcMessageParams<TCommand>,
 		completion: TCompletion,
-		callback: (params: IpcMessageParams<TCompletion>) => void,
-	): void {
+	): Promise<IpcMessageParams<TCompletion>> {
 		const id = nextIpcId();
 		this.log(`${this.appName}.sendCommandWithCompletion(${id}): name=${command.method}`);
 
-		const disposable = DOM.on(window, 'message', e => {
-			onIpc(completion, e.data as IpcMessage, params => {
-				if (params.completionId === id) {
-					disposable.dispose();
-					callback(params);
-				}
+		const promise = new Promise<IpcMessageParams<TCompletion>>(resolve => {
+			const disposable = DOM.on(window, 'message', (e: MessageEvent<IpcMessage>) => {
+				onIpc(completion, e.data, params => {
+					if (e.data.completionId === id) {
+						disposable.dispose();
+						resolve(params);
+					}
+				});
 			});
 		});
 
-		return this.postMessage({ id: id, method: command.method, params: params });
+		this.postMessage({ id: id, method: command.method, params: params, completionId: id });
+		return promise;
 	}
 
 	protected setState(state: State) {
diff --git a/src/webviews/apps/shared/appWithConfigBase.ts b/src/webviews/apps/shared/appWithConfigBase.ts
index be6ad3c..48d123d 100644
--- a/src/webviews/apps/shared/appWithConfigBase.ts
+++ b/src/webviews/apps/shared/appWithConfigBase.ts
@@ -570,7 +570,7 @@ export abstract class AppWithConfig<State extends AppStateWithConfig> extends Ap
 					return;
 				}
 
-				this.sendCommandWithCompletion(
+				void this.sendCommandWithCompletion(
 					GenerateConfigurationPreviewCommandType,
 					{
 						key: el.dataset.settingPreview!,
@@ -578,10 +578,9 @@ export abstract class AppWithConfig<State extends AppStateWithConfig> extends Ap
 						format: value,
 					},
 					DidGenerateConfigurationPreviewNotificationType,
-					params => {
-						el.innerText = params.preview ?? '';
-					},
-				);
+				).then(params => {
+					el.innerText = params.preview ?? '';
+				});
 
 				break;
 			}
diff --git a/src/webviews/protocol.ts b/src/webviews/protocol.ts
index 6bf992c..aad94f4 100644
--- a/src/webviews/protocol.ts
+++ b/src/webviews/protocol.ts
@@ -4,6 +4,7 @@ export interface IpcMessage {
 	id: string;
 	method: string;
 	params?: unknown;
+	completionId?: string;
 }
 
 abstract class IpcMessageType<Params = void> {
@@ -73,7 +74,6 @@ export const DidChangeConfigurationNotificationType = new IpcNotificationType<Di
 );
 
 export interface DidGenerateConfigurationPreviewParams {
-	completionId: string;
 	preview: string;
 }
 
diff --git a/src/webviews/webviewBase.ts b/src/webviews/webviewBase.ts
index 61063a5..2a0827d 100644
--- a/src/webviews/webviewBase.ts
+++ b/src/webviews/webviewBase.ts
@@ -216,7 +216,7 @@ export abstract class WebviewBase<State> implements Disposable {
 
 		const html = content.replace(
 			/#{(head|body|endOfBody|placement|cspSource|cspNonce|root|webroot)}/g,
-			(_substring, token) => {
+			(_substring: string, token: string) => {
 				switch (token) {
 					case 'head':
 						return head ?? '';
@@ -249,12 +249,18 @@ export abstract class WebviewBase<State> implements Disposable {
 		return html;
 	}
 
-	protected notify<T extends IpcNotificationType<any>>(type: T, params: IpcMessageParams<T>): Thenable<boolean> {
-		return this.postMessage({ id: nextIpcId(), method: type.method, params: params });
+	protected notify<T extends IpcNotificationType<any>>(
+		type: T,
+		params: IpcMessageParams<T>,
+		completionId?: string,
+	): Thenable<boolean> {
+		return this.postMessage({ id: nextIpcId(), method: type.method, params: params, completionId: completionId });
 	}
 
 	@serialize()
-	@debug<WebviewBase<State>['postMessage']>({ args: { 0: m => `(id=${m.id}, method=${m.method})` } })
+	@debug<WebviewBase<State>['postMessage']>({
+		args: { 0: m => `(id=${m.id}, method=${m.method}${m.completionId ? `, completionId=${m.completionId}` : ''})` },
+	})
 	private postMessage(message: IpcMessage): Promise<boolean> {
 		if (this._panel == null) return Promise.resolve(false);
 
diff --git a/src/webviews/webviewViewBase.ts b/src/webviews/webviewViewBase.ts
index 62bc47e..6c13375 100644
--- a/src/webviews/webviewViewBase.ts
+++ b/src/webviews/webviewViewBase.ts
@@ -17,7 +17,6 @@ import { serialize } from '../system/decorators/serialize';
 import type { TrackedUsageFeatures } from '../usageTracker';
 import type { IpcMessage, IpcMessageParams, IpcNotificationType } from './protocol';
 import { ExecuteCommandType, onIpc, WebviewReadyCommandType } from './protocol';
-import type { WebviewBase } from './webviewBase';
 
 const maxSmallIntegerV8 = 2 ** 30; // Max number that can be stored in V8's smis (small integers)
 
@@ -243,12 +242,18 @@ export abstract class WebviewViewBase<State, SerializedState = State> implements
 		return html;
 	}
 
-	protected notify<T extends IpcNotificationType<any>>(type: T, params: IpcMessageParams<T>): Thenable<boolean> {
-		return this.postMessage({ id: nextIpcId(), method: type.method, params: params });
+	protected notify<T extends IpcNotificationType<any>>(
+		type: T,
+		params: IpcMessageParams<T>,
+		completionId?: string,
+	): Thenable<boolean> {
+		return this.postMessage({ id: nextIpcId(), method: type.method, params: params, completionId: completionId });
 	}
 
 	@serialize()
-	@debug<WebviewBase<State>['postMessage']>({ args: { 0: m => `(id=${m.id}, method=${m.method})` } })
+	@debug<WebviewViewBase<State>['postMessage']>({
+		args: { 0: m => `(id=${m.id}, method=${m.method}${m.completionId ? `, completionId=${m.completionId}` : ''})` },
+	})
 	protected postMessage(message: IpcMessage) {
 		if (this._view == null) return Promise.resolve(false);
 
diff --git a/src/webviews/webviewWithConfigBase.ts b/src/webviews/webviewWithConfigBase.ts
index 8a68747..03d7b76 100644
--- a/src/webviews/webviewWithConfigBase.ts
+++ b/src/webviews/webviewWithConfigBase.ts
@@ -172,10 +172,11 @@ export abstract class WebviewWithConfigBase<State> extends WebviewBase<State> {
 								preview = 'Invalid format';
 							}
 
-							await this.notify(DidGenerateConfigurationPreviewNotificationType, {
-								completionId: e.id,
-								preview: preview,
-							});
+							await this.notify(
+								DidGenerateConfigurationPreviewNotificationType,
+								{ preview: preview },
+								e.completionId,
+							);
 						}
 					}
 				});