[UI] Loop thread to main thread WindowedAppContext

src/xenia/kernel/xam/xam_nui.cc

@@ -15,6 +15,7 @@
 #include "xenia/kernel/xam/xam_private.h"
 #include "xenia/ui/imgui_dialog.h"
 #include "xenia/ui/window.h"
+#include "xenia/ui/windowed_app_context.h"
 #include "xenia/xbox.h"
 
 namespace xe {
@@ -50,15 +51,16 @@ dword_result_t XamShowNuiTroubleshooterUI(unknown_t unk1, unknown_t unk2,
 
   auto display_window = kernel_state()->emulator()->display_window();
   xe::threading::Fence fence;
-  display_window->loop()->PostSynchronous([&]() {
-    xe::ui::ImGuiDialog::ShowMessageBox(
-        display_window, "NUI Troubleshooter",
-        "The game has indicated there is a problem with NUI (Kinect).")
-        ->Then(&fence);
-  });
-  ++xam_dialogs_shown_;
-  fence.Wait();
-  --xam_dialogs_shown_;
+  if (display_window->app_context().CallInUIThreadSynchronous([&]() {
+        xe::ui::ImGuiDialog::ShowMessageBox(
+            display_window, "NUI Troubleshooter",
+            "The game has indicated there is a problem with NUI (Kinect).")
+            ->Then(&fence);
+      })) {
+    ++xam_dialogs_shown_;
+    fence.Wait();
+    --xam_dialogs_shown_;
+  }
 
   return 0;
 }