diff --git a/src/application.c b/src/application.c
index 31ff045..34ed9f1 100644
--- a/src/application.c
+++ b/src/application.c
@@ -43,23 +43,41 @@
 static WWindow *makeMainWindow(WScreen * scr, Window window)
 {
 	WWindow *wwin;
-	XWindowAttributes attr;
 
-	if (!XGetWindowAttributes(dpy, window, &attr))
-		return NULL;
+	/* Phase 79: Wayland — synthetic IDs are not X11 windows; skip the
+	 * XGetWindowAttributes/XSelectInput calls that would crash with dpy==NULL.
+	 * The WWindow is still created so wapp->main_window_desc is non-NULL. */
+	if (dpy) {
+		XWindowAttributes attr;
 
-	wwin = wWindowCreate();
-	wwin->screen_ptr = scr;
-	wwin->client_win = window;
-	wwin->main_window = window;
-	wwin->wm_hints = wm_backend->prop_get_wm_hints(window);
+		if (!XGetWindowAttributes(dpy, window, &attr))
+			return NULL;
 
-	PropGetWMClass(window, &wwin->wm_class, &wwin->wm_instance);
+		wwin = wWindowCreate();
+		wwin->screen_ptr = scr;
+		wwin->client_win = window;
+		wwin->main_window = window;
+		wwin->wm_hints = wm_backend->prop_get_wm_hints(window);
 
-	wDefaultFillAttributes(wwin->wm_instance, wwin->wm_class, &wwin->user_flags,
-			       &wwin->defined_user_flags, True);
+		PropGetWMClass(window, &wwin->wm_class, &wwin->wm_instance);
+
+		wDefaultFillAttributes(wwin->wm_instance, wwin->wm_class, &wwin->user_flags,
+				       &wwin->defined_user_flags, True);
+
+		XSelectInput(dpy, window, attr.your_event_mask | PropertyChangeMask | StructureNotifyMask);
+	} else {
+		wwin = wWindowCreate();
+		wwin->screen_ptr = scr;
+		wwin->client_win = window;
+		wwin->main_window = window;
+		wwin->wm_hints = wm_backend->prop_get_wm_hints(window);
+
+		PropGetWMClass(window, &wwin->wm_class, &wwin->wm_instance);
+
+		wDefaultFillAttributes(wwin->wm_instance, wwin->wm_class, &wwin->user_flags,
+				       &wwin->defined_user_flags, True);
+	}
 
-	XSelectInput(dpy, window, attr.your_event_mask | PropertyChangeMask | StructureNotifyMask);
 	return wwin;
 }
 
@@ -85,7 +103,8 @@ WApplication *wApplicationCreate(WWindow * wwin)
 	if (main_window == None || main_window == scr->root_win)
 		return NULL;
 
-	{
+	/* Phase 79: skip X11 geometry validation for Wayland synthetic IDs */
+	if (dpy) {
 		Window root;
 		int foo;
 		unsigned int bar;