setOnClick(function() use ($app) { echo "Creating second window...\n"; $secondWindow = new Window('Second Window', 400, 300); $secondContainer = new Container('flex flex-col p-4 bg-green-100'); $closeButton = new Button('Close This Window', 'bg-red-500 text-white p-4 m-2 rounded hover:bg-red-600'); $closeButton->setOnClick(function() use ($secondWindow) { echo "Close button clicked in second window (ID: {$secondWindow->getWindowId()})\n"; $secondWindow->close(); }); $secondContainer->addComponent($closeButton); $secondWindow->setRoot($secondContainer); $app->addWindow($secondWindow); echo "Second window created with ID: {$secondWindow->getWindowId()}\n"; }); $mainContainer->addComponent($openButton); $mainWindow->setRoot($mainContainer); $app->addWindow($mainWindow); echo "Main window ID: {$mainWindow->getWindowId()}\n"; $app->run();