FullscreenUI: Fix various issues

- Pause menu losing key focus the first time it's opened.
- Pause menu being unopenable after close when paused.
- Key nav not being enabled after closing game via main UI.

src/core/fullscreen_ui.cpp

@@ -747,7 +747,6 @@ bool FullscreenUI::Initialize()
   else
     UpdateRunIdleState();
 
-  ForceKeyNavEnabled();
   return true;
 }
 
@@ -797,6 +796,20 @@ void FullscreenUI::OnSystemStarting()
   });
 }
 
+void FullscreenUI::OnSystemPaused()
+{
+  // NOTE: Called on CPU thread.
+  if (!IsInitialized())
+    return;
+
+  GPUThread::RunOnThread([]() {
+    if (!IsInitialized())
+      return;
+
+    UpdateRunIdleState();
+  });
+}
+
 void FullscreenUI::OnSystemResumed()
 {
   // NOTE: Called on CPU thread.
@@ -927,9 +940,14 @@ void FullscreenUI::ClosePauseMenu()
   s_state.current_main_window = MainWindowType::None;
   s_state.current_pause_submenu = PauseSubMenu::None;
   s_state.pause_menu_was_open = false;
+  ImGui::SetWindowFocus(nullptr);
   QueueResetFocus(FocusResetType::ViewChanged);
   UpdateRunIdleState();
   FixStateIfPaused();
+
+  // Present frame with menu closed. We have to defer this for a frame so imgui loses keyboard focus.
+  if (GPUThread::IsSystemPaused())
+    GPUThread::PresentCurrentFrame();
 }
 
 void FullscreenUI::OpenPauseSubMenu(PauseSubMenu submenu)
@@ -1122,12 +1140,23 @@ void FullscreenUI::ReturnToPreviousWindow()
 void FullscreenUI::ReturnToMainWindow()
 {
   ClosePauseMenu();
+
   if (GPUThread::HasGPUBackend())
+  {
     s_state.current_main_window = MainWindowType::None;
+    ImGui::SetWindowFocus(nullptr);
+  }
   else if (ShouldOpenToGameList())
+  {
     SwitchToGameList();
+    ForceKeyNavEnabled();
+  }
   else
+  {
     s_state.current_main_window = MainWindowType::Landing;
+    ForceKeyNavEnabled();
+  }
+
   UpdateRunIdleState();
   FixStateIfPaused();
 }
@@ -1943,6 +1972,8 @@ void FullscreenUI::DrawLandingWindow()
       SwitchToGameList();
     }
 
+    ImGui::SetItemDefaultFocus();
+
     if (UserThemeableHorizontalButton(
           "fullscreenui/cdrom.png", "fullscreenui/start-disc.svg", FSUI_CSTR("Start Game"),
           FSUI_CSTR("Launch a game from a file, disc, or starts the console without any disc inserted.")))
@@ -6600,8 +6631,7 @@ void FullscreenUI::DrawPauseMenu()
 
         if (MenuButtonWithoutSummary(FSUI_ICONSTR(ICON_FA_PLAY, "Resume Game")) || WantsToCloseMenu())
           ClosePauseMenu();
-        else
+        ImGui::SetItemDefaultFocus();
-          ImGui::SetItemDefaultFocus();
 
         if (MenuButtonWithoutSummary(FSUI_ICONSTR(ICON_FA_FAST_FORWARD, "Toggle Fast Forward"), false))
         {

src/core/fullscreen_ui.h

@@ -24,6 +24,7 @@ bool IsInitialized();
 bool HasActiveWindow();
 void CheckForConfigChanges(const GPUSettings& old_settings);
 void OnSystemStarting();
+void OnSystemPaused();
 void OnSystemResumed();
 void OnSystemDestroyed();
 void OnRunningGameChanged(const std::string& path, const std::string& serial, const std::string& title, GameHash hash);

src/core/imgui_overlays.cpp

@@ -626,7 +626,8 @@ void ImGuiManager::DrawFrameTimeOverlay(float& position_y, float scale, float ma
   ImGui::PushStyleVar(ImGuiStyleVar_WindowBorderSize, 0.0f);
   ImGui::PushStyleVar(ImGuiStyleVar_FramePadding, ImVec2(0.0f, 0.0f));
   ImGui::PushStyleVar(ImGuiStyleVar_FrameBorderSize, 0.0f);
-  if (ImGui::Begin("##frame_times", nullptr, ImGuiWindowFlags_NoDecoration | ImGuiWindowFlags_NoInputs))
+  if (ImGui::Begin("##frame_times", nullptr,
+                   ImGuiWindowFlags_NoDecoration | ImGuiWindowFlags_NoInputs | ImGuiWindowFlags_NoFocusOnAppearing))
   {
     ImGui::PushFont(fixed_font);
 

src/core/system.cpp

@@ -1591,6 +1591,8 @@ void System::PauseSystem(bool paused)
 
   if (paused)
   {
+    FullscreenUI::OnSystemPaused();
+
     InputManager::PauseVibration();
     InputManager::UpdateHostMouseMode();