fix multiple window example

Author: nglmercer

README.md

@@ -27,6 +27,36 @@ npm install @webviewjs/webview
 | armv7-linux-androideabi | ✅        |
 | aarch64-pc-windows-msvc | ✅        |
 
+# Important Notes
+
+## GTK Singleton Limitation on Linux
+
+On Linux, GTK is implemented as a singleton, which means you can only create **one `Application` instance**. If you try to create multiple `Application` instances, the second one will fail with an error like:
+
+```
+Failed to initialize gtk backend!: Ya existe un objeto exportado para la interfaz org.gtk.Application
+```
+
+**Correct approach for multiple windows:**
+
+```js
+// ✅ Correct: Single Application with multiple BrowserWindows
+const app = new Application();
+const window1 = app.createBrowserWindow();
+const window2 = app.createBrowserWindow();
+app.run();
+```
+
+**Incorrect approach:**
+
+```js
+// ❌ Incorrect: Multiple Application instances (will fail on Linux)
+const app1 = new Application();
+const app2 = new Application(); // This will crash!
+```
+
+This limitation is specific to Linux. On Windows and macOS, you can create multiple Application instances, though it's still recommended to use a single Application instance for consistency.
+
 # Examples
 
 ## Load external url

examples/multiple.ts

@@ -1,26 +1,54 @@
-import { Application } from '../index.js'
+import { Application, WebviewApplicationEvent } from '../index.js';
 
-const app1 = new Application();
-const window1 = app1.createBrowserWindow()
-const webview1 = window1.createWebview({ url: 'https://nodejs.org' });
-const app2 = new Application();
-const window2 = app2.createBrowserWindow()
-const webview2 = window2.createWebview({ url: 'https://wikipedia.org' });
+// Single Application instance - GTK is a singleton, so we can only have one
+const app = new Application();
+
+// Set up event handler to track when windows close
+let window1Closed = false;
+let window2Closed = false;
 
-const poll = () => {
-    if (app1.runIteration()) {
-        window1.id;
-        webview1.id;
-        setTimeout(poll, 10);
-    } else {
-        process.exit(0);
+app.bind((_err, event) => {
+  if (event.event === WebviewApplicationEvent.WindowCloseRequested) {
+    // Detect which window is closing
+    if (!window1Closed) {
+      window1Closed = true;
+      console.log('Window 1 closed');
+    } else if (!window2Closed) {
+      window2Closed = true;
+      console.log('Window 2 closed');
     }
-    if (app2.runIteration()) {
-        window2.id;
-        webview2.id;
-        setTimeout(poll, 10);
-    } else {
-        process.exit(0);
+
+    // If all windows are closed, exit the application
+    if (window1Closed && window2Closed) {
+      console.log('All windows closed, exiting application...');
+      app.exit();
     }
-};
-poll();
+  }
+});
+
+// Create first window and webview
+const window1 = app.createBrowserWindow({
+  title: 'Window 1 - Node.js',
+  width: 800,
+  height: 600,
+  x: 100,
+  y: 100,
+});
+const webview1 = window1.createWebview({ url: 'https://nodejs.org' });
+
+// Create second window and webview from the same Application
+const window2 = app.createBrowserWindow({
+  title: 'Window 2 - Wikipedia',
+  width: 800,
+  height: 600,
+  x: 920,
+  y: 100,
+});
+const webview2 = window2.createWebview({ url: 'https://wikipedia.org' });
+
+console.log('Running application with 2 windows...');
+console.log('Close both windows to exit the application.');
+
+// Run the application - this will block and keep processing events
+// until all windows are closed and app.exit() is called
+app.run();