4 files changed, 36 insertions, 2 deletions
diff --git a/include/cru/platform/gui/xcb/UiApplication.h b/include/cru/platform/gui/xcb/UiApplication.h
index fc20a4e2..42d63609 100644
--- a/include/cru/platform/gui/xcb/UiApplication.h
+++ b/include/cru/platform/gui/xcb/UiApplication.h
@@ -11,6 +11,8 @@ namespace cru::platform::gui::xcb {
 class XcbWindow;
 
 class XcbUiApplication : public XcbResource, public virtual IUiApplication {
+  friend XcbWindow;
+
  public:
   XcbUiApplication();
   ~XcbUiApplication();
@@ -57,9 +59,12 @@ class XcbUiApplication : public XcbResource, public virtual IUiApplication {
   virtual std::optional<std::vector<String>> ShowOpenDialog(
       OpenDialogOptions options);
 
-  private:
+ private:
   void HandleXEvents();
 
+  void RegisterWindow(XcbWindow* window);
+  void UnregisterWindow(XcbWindow* window);
+
  private:
   xcb_connection_t* xcb_;
   xcb_screen_t* screen_;
diff --git a/include/cru/platform/gui/xcb/Window.h b/include/cru/platform/gui/xcb/Window.h
index 8d5c629e..2d5651e7 100644
--- a/include/cru/platform/gui/xcb/Window.h
+++ b/include/cru/platform/gui/xcb/Window.h
@@ -3,9 +3,16 @@
 #include "../Window.h"
 #include "Base.h"
 
+#include <xcb/xcb.h>
+
 namespace cru::platform::gui::xcb {
+class XcbUiApplication;
+
 class XcbWindow : public XcbResource, public virtual INativeWindow {
  public:
+  explicit XcbWindow(XcbUiApplication* application);
+  ~XcbWindow() override;
+
   virtual void Close() = 0;
 
   virtual INativeWindow* GetParent() = 0;
@@ -68,5 +75,9 @@ class XcbWindow : public XcbResource, public virtual INativeWindow {
   virtual IEvent<NativeKeyEventArgs>* KeyUpEvent() = 0;
 
   virtual IInputMethodContext* GetInputMethodContext() = 0;
+
+ private:
+  XcbUiApplication* application_;
+  xcb_window_t xcb_window_;
 };
 }  // namespace cru::platform::gui::xcb
diff --git a/src/platform/gui/xcb/UiApplication.cpp b/src/platform/gui/xcb/UiApplication.cpp
index d64fc9da..139a5422 100644
--- a/src/platform/gui/xcb/UiApplication.cpp
+++ b/src/platform/gui/xcb/UiApplication.cpp
@@ -79,4 +79,12 @@ void XcbUiApplication::HandleXEvents() {
     NotImplemented();
   }
 }
+
+void XcbUiApplication::RegisterWindow(XcbWindow *window) {
+  windows_.push_back(window);
+}
+
+void XcbUiApplication::UnregisterWindow(XcbWindow *window) {
+  std::erase(windows_, window);
+}
 }  // namespace cru::platform::gui::xcb
diff --git a/src/platform/gui/xcb/Window.cpp b/src/platform/gui/xcb/Window.cpp
index 92772acf..cf4e059d 100644
--- a/src/platform/gui/xcb/Window.cpp
+++ b/src/platform/gui/xcb/Window.cpp
@@ -1 +1,11 @@
-#include <cru/platform/gui/xcb/Window.h>
+#include "cru/platform/gui/xcb/Window.h"
+#include "cru/platform/gui/xcb/UiApplication.h"
+
+namespace cru::platform::gui::xcb {
+XcbWindow::XcbWindow(XcbUiApplication* application)
+    : application_(application) {
+  application->RegisterWindow(this);
+}
+
+XcbWindow::~XcbWindow() { application_->UnregisterWindow(this); }
+}  // namespace cru::platform::gui::xcb