fix #40307

src/vs/workbench/api/electron-browser/mainThreadCommands.ts

@@ -57,7 +57,11 @@ export class MainThreadCommands implements MainThreadCommandsShape {
 	$registerCommand(id: string): void {
 		this._disposables.set(
 			id,
-			CommandsRegistry.registerCommand(id, (accessor, ...args) => this._proxy.$executeContributedCommand(id, ...args))
+			CommandsRegistry.registerCommand(id, (accessor, ...args) => {
+				return this._proxy.$executeContributedCommand(id, ...args).then(result => {
+					return revive(result, 0);
+				});
+			})
 		);
 	}
 

src/vs/workbench/api/node/extHostCommands.ts

@@ -101,7 +101,7 @@ export class ExtHostCommands implements ExtHostCommandsShape {
 				}
 			});
 
-			return this._proxy.$executeCommand<T>(id, args);
+			return this._proxy.$executeCommand<T>(id, args).then(result => revive(result, 0));
 		}
 	}