refactor(editor): streamline ImGui card management across various editors

- Refactored multiple editor classes to ensure that ImGui::End() is always called after ImGui::Begin(), enhancing state management and preventing potential rendering issues.
- Updated the DungeonEditor, GraphicsEditor, ScreenEditor, MessageEditor, MusicEditor, and SpriteEditor to follow this pattern, improving code consistency and reliability.

Benefits:
- Improves the stability of the editor UI by ensuring proper handling of ImGui state.
- Enhances code readability and maintainability by standardizing the usage of ImGui functions across different editor components.

src/app/editor/dungeon/dungeon_editor_v2.cc

@@ -443,58 +443,56 @@ void DungeonEditorV2::DrawRoomsListCard() {
   if (selector_card.Begin()) {
     if (!rom_ || !rom_->is_loaded()) {
       ImGui::Text("ROM not loaded");
-      selector_card.End();
+    } else {
-      return;
+      // Add text filter
-    }
+      static char room_filter[256] = "";
-    
+      ImGui::SetNextItemWidth(-1);
-    // Add text filter
+      if (ImGui::InputTextWithHint("##RoomFilter", ICON_MD_SEARCH " Filter rooms...", 
-    static char room_filter[256] = "";
+                                   room_filter, sizeof(room_filter))) {
-    ImGui::SetNextItemWidth(-1);
+        // Filter updated
-    if (ImGui::InputTextWithHint("##RoomFilter", ICON_MD_SEARCH " Filter rooms...", 
+      }
-                                 room_filter, sizeof(room_filter))) {
-      // Filter updated
-    }
-    
-    ImGui::Separator();
-    
-    // Scrollable room list - simple and reliable
-    if (ImGui::BeginChild("##RoomsList", ImVec2(0, 0), true,
-                          ImGuiWindowFlags_AlwaysVerticalScrollbar)) {
-      std::string filter_str = room_filter;
-      std::transform(filter_str.begin(), filter_str.end(), filter_str.begin(), ::tolower);
       
-      for (int i = 0; i < zelda3::NumberOfRooms; i++) {
+      ImGui::Separator();
-        // Get room name
+      
-        std::string room_name;
+      // Scrollable room list - simple and reliable
-        if (i < static_cast<int>(std::size(zelda3::kRoomNames))) {
+      if (ImGui::BeginChild("##RoomsList", ImVec2(0, 0), true,
-          room_name = std::string(zelda3::kRoomNames[i]);
+                            ImGuiWindowFlags_AlwaysVerticalScrollbar)) {
-        } else {
+        std::string filter_str = room_filter;
-          room_name = absl::StrFormat("Room %03X", i);
+        std::transform(filter_str.begin(), filter_str.end(), filter_str.begin(), ::tolower);
-        }
         
-        // Apply filter
+        for (int i = 0; i < zelda3::NumberOfRooms; i++) {
-        if (!filter_str.empty()) {
+          // Get room name
-          std::string name_lower = room_name;
+          std::string room_name;
-          std::transform(name_lower.begin(), name_lower.end(), 
+          if (i < static_cast<int>(std::size(zelda3::kRoomNames))) {
-                        name_lower.begin(), ::tolower);
+            room_name = std::string(zelda3::kRoomNames[i]);
-          if (name_lower.find(filter_str) == std::string::npos) {
+          } else {
-            continue;
+            room_name = absl::StrFormat("Room %03X", i);
+          }
+          
+          // Apply filter
+          if (!filter_str.empty()) {
+            std::string name_lower = room_name;
+            std::transform(name_lower.begin(), name_lower.end(), 
+                          name_lower.begin(), ::tolower);
+            if (name_lower.find(filter_str) == std::string::npos) {
+              continue;
+            }
+          }
+          
+          // Simple selectable with room ID and name
+          std::string label = absl::StrFormat("[%03X] %s", i, room_name.c_str());
+          bool is_selected = (current_room_id_ == i);
+          
+          if (ImGui::Selectable(label.c_str(), is_selected)) {
+            OnRoomSelected(i);
+          }
+          
+          if (ImGui::IsItemHovered() && ImGui::IsMouseDoubleClicked(0)) {
+            OnRoomSelected(i);
           }
         }
-        
+        ImGui::EndChild();
-        // Simple selectable with room ID and name
-        std::string label = absl::StrFormat("[%03X] %s", i, room_name.c_str());
-        bool is_selected = (current_room_id_ == i);
-        
-        if (ImGui::Selectable(label.c_str(), is_selected)) {
-          OnRoomSelected(i);
-        }
-        
-        if (ImGui::IsItemHovered() && ImGui::IsMouseDoubleClicked(0)) {
-          OnRoomSelected(i);
-        }
       }
-      ImGui::EndChild();
     }
   }
   selector_card.End();
@@ -510,92 +508,90 @@ void DungeonEditorV2::DrawEntrancesListCard() {
   if (entrances_card.Begin()) {
     if (!rom_ || !rom_->is_loaded()) {
       ImGui::Text("ROM not loaded");
-      entrances_card.End();
+    } else {
-      return;
+      // Full entrance configuration UI (matching dungeon_room_selector layout)
-    }
+      auto& current_entrance = entrances_[current_entrance_id_];
-    
+      
-    // Full entrance configuration UI (matching dungeon_room_selector layout)
+      gui::InputHexWord("Entrance ID", &current_entrance.entrance_id_);
-    auto& current_entrance = entrances_[current_entrance_id_];
+      gui::InputHexWord("Room ID", reinterpret_cast<uint16_t*>(&current_entrance.room_));
-    
+      ImGui::SameLine();
-    gui::InputHexWord("Entrance ID", &current_entrance.entrance_id_);
+      gui::InputHexByte("Dungeon ID", &current_entrance.dungeon_id_, 50.f, true);
-    gui::InputHexWord("Room ID", reinterpret_cast<uint16_t*>(&current_entrance.room_));
+      
-    ImGui::SameLine();
+      gui::InputHexByte("Blockset", &current_entrance.blockset_, 50.f, true);
-    gui::InputHexByte("Dungeon ID", &current_entrance.dungeon_id_, 50.f, true);
+      ImGui::SameLine();
-    
+      gui::InputHexByte("Music", &current_entrance.music_, 50.f, true);
-    gui::InputHexByte("Blockset", &current_entrance.blockset_, 50.f, true);
+      ImGui::SameLine();
-    ImGui::SameLine();
+      gui::InputHexByte("Floor", &current_entrance.floor_);
-    gui::InputHexByte("Music", &current_entrance.music_, 50.f, true);
+      
-    ImGui::SameLine();
+      ImGui::Separator();
-    gui::InputHexByte("Floor", &current_entrance.floor_);
+      
-    
+      gui::InputHexWord("Player X   ", &current_entrance.x_position_);
-    ImGui::Separator();
+      ImGui::SameLine();
-    
+      gui::InputHexWord("Player Y   ", &current_entrance.y_position_);
-    gui::InputHexWord("Player X   ", &current_entrance.x_position_);
+      
-    ImGui::SameLine();
+      gui::InputHexWord("Camera X", &current_entrance.camera_trigger_x_);
-    gui::InputHexWord("Player Y   ", &current_entrance.y_position_);
+      ImGui::SameLine();
-    
+      gui::InputHexWord("Camera Y", &current_entrance.camera_trigger_y_);
-    gui::InputHexWord("Camera X", &current_entrance.camera_trigger_x_);
+      
-    ImGui::SameLine();
+      gui::InputHexWord("Scroll X    ", &current_entrance.camera_x_);
-    gui::InputHexWord("Camera Y", &current_entrance.camera_trigger_y_);
+      ImGui::SameLine();
-    
+      gui::InputHexWord("Scroll Y    ", &current_entrance.camera_y_);
-    gui::InputHexWord("Scroll X    ", &current_entrance.camera_x_);
+      
-    ImGui::SameLine();
+      gui::InputHexWord("Exit", reinterpret_cast<uint16_t*>(&current_entrance.exit_), 50.f, true);
-    gui::InputHexWord("Scroll Y    ", &current_entrance.camera_y_);
+      
-    
+      ImGui::Separator();
-    gui::InputHexWord("Exit", reinterpret_cast<uint16_t*>(&current_entrance.exit_), 50.f, true);
+      ImGui::Text("Camera Boundaries");
-    
+      ImGui::Separator();
-    ImGui::Separator();
+      ImGui::Text("\t\t\t\t\tNorth         East         South         West");
-    ImGui::Text("Camera Boundaries");
+      
-    ImGui::Separator();
+      gui::InputHexByte("Quadrant", &current_entrance.camera_boundary_qn_, 50.f, true);
-    ImGui::Text("\t\t\t\t\tNorth         East         South         West");
+      ImGui::SameLine();
-    
+      gui::InputHexByte("##QE", &current_entrance.camera_boundary_qe_, 50.f, true);
-    gui::InputHexByte("Quadrant", &current_entrance.camera_boundary_qn_, 50.f, true);
+      ImGui::SameLine();
-    ImGui::SameLine();
+      gui::InputHexByte("##QS", &current_entrance.camera_boundary_qs_, 50.f, true);
-    gui::InputHexByte("##QE", &current_entrance.camera_boundary_qe_, 50.f, true);
+      ImGui::SameLine();
-    ImGui::SameLine();
+      gui::InputHexByte("##QW", &current_entrance.camera_boundary_qw_, 50.f, true);
-    gui::InputHexByte("##QS", &current_entrance.camera_boundary_qs_, 50.f, true);
+      
-    ImGui::SameLine();
+      gui::InputHexByte("Full room", &current_entrance.camera_boundary_fn_, 50.f, true);
-    gui::InputHexByte("##QW", &current_entrance.camera_boundary_qw_, 50.f, true);
+      ImGui::SameLine();
-    
+      gui::InputHexByte("##FE", &current_entrance.camera_boundary_fe_, 50.f, true);
-    gui::InputHexByte("Full room", &current_entrance.camera_boundary_fn_, 50.f, true);
+      ImGui::SameLine();
-    ImGui::SameLine();
+      gui::InputHexByte("##FS", &current_entrance.camera_boundary_fs_, 50.f, true);
-    gui::InputHexByte("##FE", &current_entrance.camera_boundary_fe_, 50.f, true);
+      ImGui::SameLine();
-    ImGui::SameLine();
+      gui::InputHexByte("##FW", &current_entrance.camera_boundary_fw_, 50.f, true);
-    gui::InputHexByte("##FS", &current_entrance.camera_boundary_fs_, 50.f, true);
+      
-    ImGui::SameLine();
+      ImGui::Separator();
-    gui::InputHexByte("##FW", &current_entrance.camera_boundary_fw_, 50.f, true);
+      
-    
+      // Entrance list - simple and reliable
-    ImGui::Separator();
+      if (ImGui::BeginChild("##EntrancesList", ImVec2(0, 0), true, 
-    
+                            ImGuiWindowFlags_AlwaysVerticalScrollbar)) {
-    // Entrance list - simple and reliable
+        for (int i = 0; i < 0x8C; i++) {
-    if (ImGui::BeginChild("##EntrancesList", ImVec2(0, 0), true, 
+          // The last seven are spawn points
-                          ImGuiWindowFlags_AlwaysVerticalScrollbar)) {
+          std::string entrance_name;
-      for (int i = 0; i < 0x8C; i++) {
+          if (i < 0x85) {
-        // The last seven are spawn points
+            entrance_name = std::string(zelda3::kEntranceNames[i]);
-        std::string entrance_name;
+          } else {
-        if (i < 0x85) {
+            entrance_name = absl::StrFormat("Spawn Point %d", i - 0x85);
-          entrance_name = std::string(zelda3::kEntranceNames[i]);
+          }
-        } else {
+          
-          entrance_name = absl::StrFormat("Spawn Point %d", i - 0x85);
+          // Get associated room name
-        }
+          int room_id = entrances_[i].room_;
-        
+          std::string room_name = "Unknown";
-        // Get associated room name
+          if (room_id >= 0 && room_id < static_cast<int>(std::size(zelda3::kRoomNames))) {
-        int room_id = entrances_[i].room_;
+            room_name = std::string(zelda3::kRoomNames[room_id]);
-        std::string room_name = "Unknown";
+          }
-        if (room_id >= 0 && room_id < static_cast<int>(std::size(zelda3::kRoomNames))) {
+          
-          room_name = std::string(zelda3::kRoomNames[room_id]);
+          std::string label = absl::StrFormat("[%02X] %s -> %s", 
-        }
+                                              i, entrance_name.c_str(), room_name.c_str());
-        
+          
-        std::string label = absl::StrFormat("[%02X] %s -> %s", 
+          bool is_selected = (current_entrance_id_ == i);
-                                            i, entrance_name.c_str(), room_name.c_str());
+          if (ImGui::Selectable(label.c_str(), is_selected)) {
-        
+            current_entrance_id_ = i;
-        bool is_selected = (current_entrance_id_ == i);
+            OnEntranceSelected(i);
-        if (ImGui::Selectable(label.c_str(), is_selected)) {
+          }
-          current_entrance_id_ = i;
-          OnEntranceSelected(i);
         }
+        ImGui::EndChild();
       }
-      ImGui::EndChild();
     }
   }
   entrances_card.End();
@@ -757,12 +753,8 @@ void DungeonEditorV2::DrawRoomGraphicsCard() {
   if (graphics_card.Begin()) {
     if (!rom_ || !rom_->is_loaded()) {
       ImGui::Text("ROM not loaded");
-      graphics_card.End();
+    } else if (current_room_id_ >= 0 && current_room_id_ < static_cast<int>(rooms_.size())) {
-      return;
+      // Show graphics for current room
-    }
-    
-    // Show graphics for current room
-    if (current_room_id_ >= 0 && current_room_id_ < static_cast<int>(rooms_.size())) {
       auto& room = rooms_[current_room_id_];
       
       ImGui::Text("Room %03X Graphics", current_room_id_);

src/app/editor/graphics/graphics_editor.cc

@@ -112,28 +112,29 @@ absl::Status GraphicsEditor::Update() {
   prototype_card.SetDefaultSize(600, 500);
 
   // Get visibility flags from card manager and pass to Begin()
+  // Always call End() after Begin() - End() handles ImGui state safely
   if (sheet_editor_card.Begin(card_manager.GetVisibilityFlag("graphics.sheet_editor"))) {
     status_ = UpdateGfxEdit();
-    sheet_editor_card.End();
   }
+  sheet_editor_card.End();
 
   if (sheet_browser_card.Begin(card_manager.GetVisibilityFlag("graphics.sheet_browser"))) {
     if (asset_browser_.Initialized == false) {
       asset_browser_.Initialize(gfx::Arena::Get().gfx_sheets());
     }
     asset_browser_.Draw(gfx::Arena::Get().gfx_sheets());
-    sheet_browser_card.End();
   }
+  sheet_browser_card.End();
 
   if (player_anims_card.Begin(card_manager.GetVisibilityFlag("graphics.player_animations"))) {
     status_ = UpdateLinkGfxView();
-    player_anims_card.End();
   }
+  player_anims_card.End();
 
   if (prototype_card.Begin(card_manager.GetVisibilityFlag("graphics.prototype_viewer"))) {
     status_ = UpdateScadView();
-    prototype_card.End();
   }
+  prototype_card.End();
 
   CLEAR_AND_RETURN_STATUS(status_)
   return absl::OkStatus();

src/app/editor/graphics/screen_editor.cc

@@ -109,30 +109,29 @@ absl::Status ScreenEditor::Update() {
   naming_screen_card.SetDefaultSize(500, 400);
 
   // Get visibility flags from card manager and pass to Begin()
+  // Always call End() after Begin() - End() handles ImGui state safely
   if (dungeon_maps_card.Begin(card_manager.GetVisibilityFlag("screen.dungeon_maps"))) {
     DrawDungeonMapsEditor();
   }
   dungeon_maps_card.End();
-
+  
   if (inventory_menu_card.Begin(card_manager.GetVisibilityFlag("screen.inventory_menu"))) {
     DrawInventoryMenuEditor();
-  
   }
   inventory_menu_card.End();
-
+  
   if (overworld_map_card.Begin(card_manager.GetVisibilityFlag("screen.overworld_map"))) {
     DrawOverworldMapEditor();
   }
   overworld_map_card.End();
-
+  
   if (title_screen_card.Begin(card_manager.GetVisibilityFlag("screen.title_screen"))) {
     DrawTitleScreenEditor();
-  
   }
   title_screen_card.End();
-
+  
   if (naming_screen_card.Begin(card_manager.GetVisibilityFlag("screen.naming_screen"))) {
-    DrawNamingScreenEditor();  
+    DrawNamingScreenEditor();
   }
   naming_screen_card.End();
 

src/app/editor/message/message_editor.cc

@@ -151,8 +151,8 @@ absl::Status MessageEditor::Update() {
     list_card.SetDefaultSize(400, 600);
     if (list_card.Begin()) {
       DrawMessageList();
-      list_card.End();
     }
+    list_card.End();
   }
   
   // Message Editor Card
@@ -161,8 +161,8 @@ absl::Status MessageEditor::Update() {
     editor_card.SetDefaultSize(500, 600);
     if (editor_card.Begin()) {
       DrawCurrentMessage();
-      editor_card.End();
     }
+    editor_card.End();
   }
   
   // Font Atlas Card
@@ -172,8 +172,8 @@ absl::Status MessageEditor::Update() {
     if (font_card.Begin()) {
       DrawFontAtlas();
       DrawExpandedMessageSettings();
-      font_card.End();
     }
+    font_card.End();
   }
   
   // Dictionary Card
@@ -184,8 +184,8 @@ absl::Status MessageEditor::Update() {
       DrawTextCommands();
       DrawSpecialCharacters();
       DrawDictionary();
-      dict_card.End();
     }
+    dict_card.End();
   }
   
   return absl::OkStatus();

src/app/editor/music/music_editor.cc

@@ -48,20 +48,20 @@ absl::Status MusicEditor::Update() {
   // Music Tracker Card
   if (tracker_card.Begin(card_manager.GetVisibilityFlag("music.tracker"))) {
     DrawTrackerView();
-    tracker_card.End();
   }
+  tracker_card.End();
   
   // Instrument Editor Card
   if (instrument_card.Begin(card_manager.GetVisibilityFlag("music.instrument_editor"))) {
     DrawInstrumentEditor();
-    instrument_card.End();
   }
+  instrument_card.End();
   
   // Assembly View Card
   if (assembly_card.Begin(card_manager.GetVisibilityFlag("music.assembly"))) {
     assembly_editor_.InlineUpdate();
-    assembly_card.End();
   }
+  assembly_card.End();
 
   return absl::OkStatus();
 }

src/app/editor/sprite/sprite_editor.cc

@@ -57,15 +57,16 @@ absl::Status SpriteEditor::Update() {
   custom_card.SetDefaultSize(800, 600);
 
   // Get visibility flags from card manager and pass to Begin()
+  // Always call End() after Begin() - End() handles ImGui state safely
   if (vanilla_card.Begin(card_manager.GetVisibilityFlag("sprite.vanilla_editor"))) {
     DrawVanillaSpriteEditor();
-    vanilla_card.End();
   }
+  vanilla_card.End();
 
   if (custom_card.Begin(card_manager.GetVisibilityFlag("sprite.custom_editor"))) {
     DrawCustomSprites();
-    custom_card.End();
   }
+  custom_card.End();
 
   return status_.ok() ? absl::OkStatus() : status_;
 }

src/app/gui/app/editor_layout.cc

@@ -250,12 +250,14 @@ void EditorCard::SetPosition(Position pos) {
 bool EditorCard::Begin(bool* p_open) {
   // Check visibility flag first - if provided and false, don't show the card
   if (p_open && !*p_open) {
+    imgui_begun_ = false;
     return false;
   }
   
   // Handle icon-collapsed state
   if (icon_collapsible_ && collapsed_to_icon_) {
     DrawFloatingIconButton();
+    imgui_begun_ = false;
     return false;
   }
   
@@ -320,6 +322,9 @@ bool EditorCard::Begin(bool* p_open) {
                              closable_ ? actual_p_open : nullptr, 
                              flags);
   
+  // Mark that ImGui::Begin() was called - End() must always be called now
+  imgui_begun_ = true;
+  
   // Register card window for test automation
   if (ImGui::GetCurrentWindow() && ImGui::GetCurrentWindow()->ID != 0) {
     std::string card_path = absl::StrFormat("EditorCard:%s", title_.c_str());
@@ -332,12 +337,16 @@ bool EditorCard::Begin(bool* p_open) {
 }
 
 void EditorCard::End() {
-  // Check if window was focused this frame
+  // Only call ImGui::End() and pop styles if ImGui::Begin() was called
-  focused_ = ImGui::IsWindowFocused(ImGuiFocusedFlags_ChildWindows);
+  if (imgui_begun_) {
-  
+    // Check if window was focused this frame
-  ImGui::End();
+    focused_ = ImGui::IsWindowFocused(ImGuiFocusedFlags_ChildWindows);
-  ImGui::PopStyleColor(2);
+    
-  ImGui::PopStyleVar(2);
+    ImGui::End();
+    ImGui::PopStyleColor(2);
+    ImGui::PopStyleVar(2);
+    imgui_begun_ = false;
+  }
 }
 
 void EditorCard::Focus() {

src/app/gui/app/editor_layout.h

@@ -98,9 +98,9 @@ class Toolset {
  * tile_card.SetPosition(CardPosition::Right);
  * 
  * if (tile_card.Begin()) {
- *   // Draw tile selector content
+ *   // Draw tile selector content when visible
- *   tile_card.End();
  * }
+ * tile_card.End();  // Always call End() after Begin()
  * ```
  */
 class EditorCard {
@@ -154,6 +154,7 @@ class EditorCard {
   bool first_draw_ = true;
   bool focused_ = false;
   bool* p_open_ = nullptr;
+  bool imgui_begun_ = false;  // Track if ImGui::Begin() was called
   
   // UX enhancements
   bool headless_ = false;  // Minimal chrome, no title bar