diff --git a/examples/ui.cpp b/examples/ui.cpp
index a1c59939..6facb9ff 100644
--- a/examples/ui.cpp
+++ b/examples/ui.cpp
@@ -7,6 +7,8 @@
 #include <psemek/ui/default_element_factory.hpp>
 #include <psemek/ui/font.hpp>
 
+#include <psemek/async/event_loop.hpp>
+
 #include <psemek/geom/camera.hpp>
 
 using namespace psemek;
@@ -16,6 +18,7 @@ struct ui_example
 {
 	ui_example()
 		: app("UI example", 1)
+		, ui_controller(&loop)
 	{
 		auto style = std::make_shared<ui::style>();
 		style->font = ui::make_default_9x12_font();
@@ -23,7 +26,11 @@ struct ui_example
 		element_factory.set_style(style);
 
 		auto screen = element_factory.make_screen();
-		screen->add(element_factory.make_button("Test"), ui::screen::x_policy::center, ui::screen::y_policy::center);
+		auto button = element_factory.make_button("Test");
+		button->on_click([button = button.get()]{
+			button->label()->set_text(std::string(button->label()->text()) + "0");
+		});
+		screen->add(button, ui::screen::x_policy::center, ui::screen::y_policy::center);
 
 		ui_controller.set_root(std::move(screen));
 	}
@@ -52,12 +59,20 @@ struct ui_example
 		ui_controller.event(ui::mouse_click{ui::mouse_button::left, false});
 	}
 
+	void update() override;
+
 	void present() override;
 
+	async::event_loop loop;
 	ui::controller ui_controller;
 	ui::default_element_factory element_factory;
 };
 
+void ui_example::update()
+{
+	loop.pump();
+}
+
 void ui_example::present()
 {
 	gl::ClearColor(0.8f, 0.8f, 0.8f, 1.f);
diff --git a/libs/ui/include/psemek/ui/controller.hpp b/libs/ui/include/psemek/ui/controller.hpp
index d164944c..b5692d12 100644
--- a/libs/ui/include/psemek/ui/controller.hpp
+++ b/libs/ui/include/psemek/ui/controller.hpp
@@ -10,7 +10,7 @@ namespace psemek::ui
 
 	struct controller
 	{
-		controller();
+		controller(async::executor * loop);
 		~controller();
 
 		std::shared_ptr<element> set_root(std::shared_ptr<element> r);
diff --git a/libs/ui/source/controller.cpp b/libs/ui/source/controller.cpp
index cf66cddc..b9c8cd24 100644
--- a/libs/ui/source/controller.cpp
+++ b/libs/ui/source/controller.cpp
@@ -1,7 +1,6 @@
 #include <psemek/ui/controller.hpp>
 
 #include <psemek/ui/painter_impl.hpp>
-#include <psemek/async/event_loop.hpp>
 #include <psemek/gfx/gl.hpp>
 #include <psemek/util/recursive.hpp>
 #include <psemek/geom/camera.hpp>
@@ -11,15 +10,21 @@ namespace psemek::ui
 
 	struct controller::impl
 	{
+		async::executor * loop;
 		painter_impl painter;
 		std::shared_ptr<element> root;
-		async::event_loop loop;
 		geom::box<float, 2> shape{{{0.f, 0.f}, {0.f, 0.f}}};
 
+		impl(async::executor * loop);
+
 		template <typename E>
 		bool event(E const & e);
 	};
 
+	controller::impl::impl(async::executor * loop)
+		: loop(loop)
+	{}
+
 	template <typename E>
 	bool controller::impl::event(E const & e)
 	{
@@ -36,8 +41,8 @@ namespace psemek::ui
 		return false;
 	}
 
-	controller::controller()
-		: pimpl_{make_impl()}
+	controller::controller(async::executor * loop)
+		: pimpl_{make_impl(loop)}
 	{}
 
 	controller::~controller() = default;
@@ -49,7 +54,7 @@ namespace psemek::ui
 		if (old) old->set_loop(nullptr);
 		if (impl().root)
 		{
-			impl().root->set_loop(&impl().loop);
+			impl().root->set_loop(impl().loop);
 			impl().root->reshape(impl().shape);
 		}
 		return old;