--- /dev/null
+#ifndef MSP_GRAPHICS_DISPLAY_PRIVATE_H_
+#define MSP_GRAPHICS_DISPLAY_PRIVATE_H_
+
+#include <map>
+#include "display.h"
+#include "display_platform.h"
+#include "window_private.h"
+
+namespace Msp {
+namespace Graphics {
+
+struct Display::Private
+{
+ DisplayHandle display;
+ std::map<WindowHandle, Window *> windows;
+};
+
+} // namespace Graphics
+} // namespace Msp
+
+#endif