diff --git a/CMakeLists.txt b/CMakeLists.txt
index 121cf19..ce375e9 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -96,6 +96,8 @@ file(GLOB PROJECT_SRC CONFIGURE_DEPENDS
      src/imgui/*.hpp
      src/imgui/window/*.cpp
      src/imgui/window/*.hpp
+     src/imgui/popup/*.cpp
+     src/imgui/popup/*.hpp
      src/imgui/wizard/*.cpp
      src/imgui/wizard/*.hpp
      src/util/*.cpp
diff --git a/src/imgui/autosave_restore.cpp b/src/imgui/autosave_restore.cpp
index 0d6af65..972da3e 100644
--- a/src/imgui/autosave_restore.cpp
+++ b/src/imgui/autosave_restore.cpp
@@ -11,11 +11,16 @@ namespace anm2ed::imgui
 {
   void AutosaveRestore::update(Manager& manager)
   {
-    if (!manager.autosaveFiles.empty() && !popup.is_open()) popup.open();
+    if (!isInitialized)
+    {
+      isInitialized = true;
+      isRestoreAvailable = !manager.autosaveFiles.empty();
+      if (isRestoreAvailable) popup.open();
+    }
 
     popup.trigger();
 
-    if (ImGui::BeginPopupModal(popup.label(), &popup.isOpen, ImGuiWindowFlags_NoResize))
+    if (isRestoreAvailable && ImGui::BeginPopupModal(popup.label(), &popup.isOpen, ImGuiWindowFlags_NoResize))
     {
       ImGui::TextUnformatted(localize.get(LABEL_RESTORE_AUTOSAVES_PROMPT));
 
@@ -37,6 +42,7 @@ namespace anm2ed::imgui
       if (ImGui::Button(localize.get(BASIC_YES), widgetSize))
       {
         manager.autosave_files_open();
+        isRestoreAvailable = false;
         popup.close();
       }
 
@@ -45,6 +51,7 @@ namespace anm2ed::imgui
       if (ImGui::Button(localize.get(BASIC_NO), widgetSize))
       {
         manager.autosave_files_clear();
+        isRestoreAvailable = false;
         popup.close();
       }
 
diff --git a/src/imgui/autosave_restore.hpp b/src/imgui/autosave_restore.hpp
index 9eda88f..2a36185 100644
--- a/src/imgui/autosave_restore.hpp
+++ b/src/imgui/autosave_restore.hpp
@@ -8,6 +8,8 @@ namespace anm2ed::imgui
   class AutosaveRestore
   {
     PopupHelper popup{PopupHelper(LABEL_WELCOME_RESTORE_POPUP, imgui::POPUP_SMALL_NO_HEIGHT)};
+    bool isInitialized{};
+    bool isRestoreAvailable{};
 
   public:
     void update(Manager&);
diff --git a/src/imgui/popup/item_properties.cpp b/src/imgui/popup/item_properties.cpp
new file mode 100644
index 0000000..6b7b74a
--- /dev/null
+++ b/src/imgui/popup/item_properties.cpp
@@ -0,0 +1,218 @@
+#include "item_properties.hpp"
+
+#include <format>
+
+#include "imgui_.hpp"
+
+using namespace anm2ed::resource;
+using namespace anm2ed::types;
+
+namespace anm2ed::imgui::popup
+{
+  void ItemProperties::reset()
+  {
+    addItemName.clear();
+    addItemID = -1;
+    addItemSpritesheetID = {};
+  }
+
+  std::set<int> ItemProperties::unused_items_get(anm2::Anm2& anm2, anm2::Animation* animation, anm2::Type type)
+  {
+    if (!animation) return {};
+    if (type == anm2::LAYER) return anm2.layers_unused(*animation);
+    if (type == anm2::NULL_) return anm2.nulls_unused(*animation);
+    return {};
+  }
+
+  void ItemProperties::open()
+  {
+    reset();
+    popup.open();
+  }
+
+  void ItemProperties::update(Manager& manager, Settings& settings, Document& document, anm2::Animation* animation,
+                              anm2::Reference& reference,
+                              const std::function<void(anm2::Type, int)>& referenceSetItem)
+  {
+    auto& anm2 = document.anm2;
+
+    popup.trigger();
+
+    if (ImGui::BeginPopupModal(popup.label(), &popup.isOpen, ImGuiWindowFlags_NoResize))
+    {
+      auto close = [&]()
+      {
+        reset();
+        popup.close();
+      };
+
+      auto& type = settings.timelineAddItemType;
+      auto& destination = settings.timelineAddItemDestination;
+      auto& source = settings.timelineAddItemSource;
+
+      auto contentHeight = ImGui::GetContentRegionAvail().y - ImGui::GetFrameHeightWithSpacing();
+      if (contentHeight < 1.0f) contentHeight = 1.0f;
+
+      if (ImGui::BeginChild("##Content", ImVec2(0, contentHeight), ImGuiChildFlags_Borders))
+      {
+        auto spaced_pair = [](const std::function<void()>& left, const std::function<void()>& right)
+        {
+          auto startX = ImGui::GetCursorPosX();
+          auto secondX = startX + ImGui::GetContentRegionAvail().x * 0.5f;
+          left();
+          ImGui::SameLine();
+          ImGui::SetCursorPosX(secondX);
+          right();
+        };
+
+        ImGui::SeparatorText(localize.get(LABEL_TYPE));
+
+        spaced_pair(
+            [&]()
+            {
+              ImGui::RadioButton(localize.get(LABEL_LAYER), &type, anm2::LAYER);
+              ImGui::SetItemTooltip("%s", localize.get(TOOLTIP_LAYER_TYPE));
+            },
+            [&]()
+            {
+              ImGui::RadioButton(localize.get(LABEL_NULL), &type, anm2::NULL_);
+              ImGui::SetItemTooltip("%s", localize.get(TOOLTIP_NULL_TYPE));
+            });
+
+        ImGui::SeparatorText(localize.get(LABEL_SOURCE));
+
+        auto isUnusedItems = animation && !unused_items_get(anm2, animation, (anm2::Type)type).empty();
+        spaced_pair(
+            [&]()
+            {
+              ImGui::RadioButton(localize.get(LABEL_NEW), &source, source::NEW);
+              ImGui::SetItemTooltip("%s", localize.get(TOOLTIP_NEW_ITEM));
+            },
+            [&]()
+            {
+              ImGui::BeginDisabled(!isUnusedItems);
+              ImGui::RadioButton(localize.get(LABEL_EXISTING), &source, source::EXISTING);
+              ImGui::EndDisabled();
+              ImGui::SetItemTooltip("%s", isUnusedItems ? localize.get(TOOLTIP_USE_EXISTING_ITEM)
+                                                        : localize.get(TOOLTIP_NO_UNUSED_ITEMS));
+            });
+
+        ImGui::SeparatorText(localize.get(LABEL_DESTINATION));
+
+        spaced_pair(
+            [&]()
+            {
+              ImGui::RadioButton(localize.get(LABEL_ALL_ANIMATIONS), &destination, destination::ALL);
+              ImGui::SetItemTooltip("%s", localize.get(TOOLTIP_ITEM_ALL_ANIMATIONS));
+            },
+            [&]()
+            {
+              ImGui::RadioButton(localize.get(LABEL_THIS_ANIMATION), &destination, destination::THIS);
+              ImGui::SetItemTooltip("%s", localize.get(TOOLTIP_ITEM_THIS_ANIMATION));
+            });
+
+        if (source == source::NEW)
+        {
+          ImGui::SeparatorText(localize.get(LABEL_OPTIONS));
+
+          input_text_string(localize.get(BASIC_NAME), &addItemName);
+          ImGui::SetItemTooltip("%s", localize.get(TOOLTIP_ITEM_NAME));
+          if (type == anm2::LAYER)
+          {
+            combo_id_mapped(localize.get(LABEL_SPRITESHEET), &addItemSpritesheetID, document.spritesheet.ids,
+                            document.spritesheet.labels);
+            ImGui::SetItemTooltip("%s", localize.get(TOOLTIP_LAYER_SPRITESHEET));
+          }
+          else if (type == anm2::NULL_)
+          {
+            ImGui::Checkbox(localize.get(LABEL_RECT), &addItemIsShowRect);
+            ImGui::SetItemTooltip("%s", localize.get(TOOLTIP_NULL_RECT));
+          }
+        }
+        else if (animation)
+        {
+          ImGui::SeparatorText(localize.get(type == anm2::LAYER ? LABEL_LAYER : LABEL_NULL));
+
+          if (ImGui::BeginChild("##Existing Items", ImVec2(0, 0)))
+          {
+            auto unusedItems = unused_items_get(anm2, animation, (anm2::Type)type);
+            if (addItemID != -1 && !unusedItems.contains(addItemID)) addItemID = -1;
+
+            for (auto id : unusedItems)
+            {
+              auto isSelected = addItemID == id;
+
+              ImGui::PushID(id);
+
+              if (type == anm2::LAYER)
+              {
+                if (auto it = anm2.content.layers.find(id); it != anm2.content.layers.end())
+                {
+                  auto& layer = it->second;
+                  auto label = std::vformat(localize.get(FORMAT_LAYER),
+                                            std::make_format_args(id, layer.name, layer.spritesheetID));
+                  if (ImGui::Selectable(label.c_str(), isSelected))
+                  {
+                    addItemID = id;
+                    addItemSpritesheetID = layer.spritesheetID;
+                  }
+                }
+              }
+              else if (type == anm2::NULL_)
+              {
+                if (auto it = anm2.content.nulls.find(id); it != anm2.content.nulls.end())
+                {
+                  auto& null = it->second;
+                  auto label = std::vformat(localize.get(FORMAT_NULL), std::make_format_args(id, null.name));
+                  if (ImGui::Selectable(label.c_str(), isSelected))
+                  {
+                    addItemID = id;
+                    addItemIsShowRect = null.isShowRect;
+                  }
+                }
+              }
+
+              ImGui::PopID();
+            }
+          }
+          ImGui::EndChild();
+        }
+      }
+      ImGui::EndChild();
+
+      auto widgetSize = widget_size_with_row_get(2);
+
+      ImGui::BeginDisabled(source == source::EXISTING && addItemID == -1);
+      shortcut(manager.chords[SHORTCUT_CONFIRM]);
+      if (ImGui::Button(localize.get(BASIC_ADD), widgetSize))
+      {
+        anm2::Reference addReference{};
+        int insertBeforeID = reference.itemType == anm2::LAYER ? reference.itemID : -1;
+
+        document.snapshot(localize.get(EDIT_ADD_ITEM));
+        if (type == anm2::LAYER)
+          addReference = anm2.layer_animation_add({reference.animationIndex, anm2::LAYER, addItemID}, insertBeforeID,
+                                                  addItemName, addItemSpritesheetID, (destination::Type)destination);
+        else if (type == anm2::NULL_)
+          addReference = anm2.null_animation_add({reference.animationIndex, anm2::NULL_, addItemID}, addItemName,
+                                                 addItemIsShowRect, (destination::Type)destination);
+
+        document.change(Document::ITEMS);
+
+        referenceSetItem(addReference.itemType, addReference.itemID);
+
+        close();
+      }
+      ImGui::EndDisabled();
+      ImGui::SetItemTooltip("%s", localize.get(TOOLTIP_ADD_ITEM));
+
+      ImGui::SameLine();
+
+      shortcut(manager.chords[SHORTCUT_CANCEL]);
+      if (ImGui::Button(localize.get(BASIC_CANCEL), widgetSize)) close();
+      ImGui::SetItemTooltip("%s", localize.get(TOOLTIP_CANCEL_ADD_ITEM));
+
+      ImGui::EndPopup();
+    }
+  }
+}
diff --git a/src/imgui/popup/item_properties.hpp b/src/imgui/popup/item_properties.hpp
new file mode 100644
index 0000000..4391e4a
--- /dev/null
+++ b/src/imgui/popup/item_properties.hpp
@@ -0,0 +1,30 @@
+#pragma once
+
+#include <functional>
+#include <set>
+#include <string>
+
+#include "document.hpp"
+#include "manager.hpp"
+#include "settings.hpp"
+#include "strings.hpp"
+
+namespace anm2ed::imgui::popup
+{
+  class ItemProperties
+  {
+    PopupHelper popup{PopupHelper(LABEL_TIMELINE_PROPERTIES_POPUP, POPUP_NORMAL)};
+    std::string addItemName{"New Item"};
+    bool addItemIsShowRect{};
+    int addItemID{-1};
+    int addItemSpritesheetID{-1};
+
+    void reset();
+    std::set<int> unused_items_get(anm2::Anm2&, anm2::Animation*, anm2::Type);
+
+  public:
+    void open();
+    void update(Manager&, Settings&, Document&, anm2::Animation*, anm2::Reference&,
+                const std::function<void(anm2::Type, int)>&);
+  };
+}
diff --git a/src/imgui/window/animation_preview.cpp b/src/imgui/window/animation_preview.cpp
index 33a2719..cf896fb 100644
--- a/src/imgui/window/animation_preview.cpp
+++ b/src/imgui/window/animation_preview.cpp
@@ -1009,6 +1009,10 @@ namespace anm2ed::imgui
         auto useTool = tool;
         auto step = isMod ? STEP_FAST : STEP;
         mousePos = position_translate(zoom, pan, to_vec2(ImGui::GetMousePos()) - to_vec2(cursorScreenPos));
+        auto selectedNullIt = reference.itemType == anm2::NULL_ ? anm2.content.nulls.find(reference.itemID)
+                                                                : anm2.content.nulls.end();
+        bool isSelectedNullRect = selectedNullIt != anm2.content.nulls.end() && selectedNullIt->second.isShowRect;
+        auto null_rect_top_left = [](const anm2::Frame& frame) { return frame.position - (frame.scale * 0.5f); };
 
         if (isMouseMiddleDown) useTool = tool::PAN;
         if (tool == tool::MOVE && isMouseRightDown) useTool = tool::SCALE;
@@ -1031,6 +1035,15 @@ namespace anm2ed::imgui
 
         auto frame_change_apply = [&](anm2::FrameChange frameChange, anm2::ChangeType changeType = anm2::ADJUST)
         { item->frames_change(frameChange, reference.itemType, changeType, frames); };
+        auto null_rect_change = [&](vec2 topLeft, vec2 rectSize)
+        {
+          topLeft = vec2(ivec2(topLeft));
+          rectSize = vec2(ivec2(rectSize));
+          frame_change_apply({.positionX = topLeft.x + rectSize.x * 0.5f,
+                              .positionY = topLeft.y + rectSize.y * 0.5f,
+                              .scaleX = rectSize.x,
+                              .scaleY = rectSize.y});
+        };
 
         auto& toolInfo = tool::INFO[useTool];
         auto& areaType = toolInfo.areaType;
@@ -1054,13 +1067,20 @@ namespace anm2ed::imgui
               document.snapshot(localize.get(EDIT_FRAME_POSITION));
               if (isToolMouseClicked)
               {
-                moveOffset = settings.inputIsMoveToolSnapToMouse ? vec2() : mousePos - frame->position;
+                auto origin = isSelectedNullRect ? null_rect_top_left(*frame) : frame->position;
+                moveOffset = settings.inputIsMoveToolSnapToMouse ? vec2() : mousePos - origin;
                 isMoveDragging = true;
               }
             }
             if (isToolMouseDown && isMoveDragging)
-              frame_change_apply(
-                  {.positionX = (int)(mousePos.x - moveOffset.x), .positionY = (int)(mousePos.y - moveOffset.y)});
+            {
+              auto position = mousePos - moveOffset;
+              if (isSelectedNullRect)
+                frame_change_apply({.positionX = (int)(position.x + frame->scale.x * 0.5f),
+                                    .positionY = (int)(position.y + frame->scale.y * 0.5f)});
+              else
+                frame_change_apply({.positionX = (int)position.x, .positionY = (int)position.y});
+            }
 
             if (isLeftPressed) frame_change_apply({.positionX = step}, anm2::SUBTRACT);
             if (isRightPressed) frame_change_apply({.positionX = step}, anm2::ADD);
@@ -1082,12 +1102,34 @@ namespace anm2ed::imgui
             break;
           case tool::SCALE:
             if (!item || !frame || frames.empty()) break;
-            if (isToolBegin) document.snapshot(localize.get(EDIT_FRAME_SCALE));
+            if (isToolBegin)
+            {
+              document.snapshot(localize.get(EDIT_FRAME_SCALE));
+              if (isToolMouseClicked && isSelectedNullRect) nullRectScaleAnchor = null_rect_top_left(*frame);
+            }
             if (isToolMouseDown)
             {
-              auto scale = frame->scale + vec2(mouseDelta.x, mouseDelta.y);
-              if (isMod) scale = {scale.x, scale.x};
-              frame_change_apply({.scaleX = scale.x, .scaleY = scale.y});
+              if (isSelectedNullRect)
+              {
+                auto size = mousePos - nullRectScaleAnchor;
+                if (isMod)
+                {
+                  auto squareSize = std::max(std::abs(size.x), std::abs(size.y));
+                  size = {std::copysign(squareSize, size.x), std::copysign(squareSize, size.y)};
+                }
+
+                auto minPoint = glm::min(nullRectScaleAnchor, nullRectScaleAnchor + size);
+                auto maxPoint = glm::max(nullRectScaleAnchor, nullRectScaleAnchor + size);
+                minPoint = vec2(ivec2(minPoint));
+                maxPoint = vec2(ivec2(maxPoint));
+                null_rect_change(minPoint, maxPoint - minPoint);
+              }
+              else
+              {
+                auto scale = frame->scale + vec2(mouseDelta.x, mouseDelta.y);
+                if (isMod) scale = {scale.x, scale.x};
+                frame_change_apply({.scaleX = scale.x, .scaleY = scale.y});
+              }
             }
 
             if (isLeftPressed) frame_change_apply({.scaleX = step}, anm2::SUBTRACT);
@@ -1106,7 +1148,19 @@ namespace anm2ed::imgui
               }
             }
 
-            if (isToolEnd) document.change(Document::FRAMES);
+            if (isToolEnd)
+            {
+              if (isSelectedNullRect)
+              {
+                auto topLeft = null_rect_top_left(*frame);
+                auto minPoint = glm::min(topLeft, topLeft + frame->scale);
+                auto maxPoint = glm::max(topLeft, topLeft + frame->scale);
+                minPoint = vec2(ivec2(minPoint));
+                maxPoint = vec2(ivec2(maxPoint));
+                null_rect_change(minPoint, maxPoint - minPoint);
+              }
+              document.change(Document::FRAMES);
+            }
             break;
           case tool::ROTATE:
             if (!item || !frame || frames.empty()) break;
diff --git a/src/imgui/window/animation_preview.hpp b/src/imgui/window/animation_preview.hpp
index 3b591e2..1ed137b 100644
--- a/src/imgui/window/animation_preview.hpp
+++ b/src/imgui/window/animation_preview.hpp
@@ -29,6 +29,7 @@ namespace anm2ed::imgui
     bool hasPendingZoomPanAdjust{};
     bool isMoveDragging{};
     glm::vec2 moveOffset{};
+    glm::vec2 nullRectScaleAnchor{};
     std::filesystem::path renderTempDirectory{};
     std::vector<std::filesystem::path> renderTempFrames{};
     std::vector<double> renderTempFrameDurations{};
diff --git a/src/imgui/window/timeline.cpp b/src/imgui/window/timeline.cpp
index cce6f33..71e55a6 100644
--- a/src/imgui/window/timeline.cpp
+++ b/src/imgui/window/timeline.cpp
@@ -643,21 +643,6 @@ namespace anm2ed::imgui
       };
     };
 
-    auto item_properties_reset = [&]()
-    {
-      addItemName.clear();
-      addItemSpritesheetID = {};
-      addItemID = -1;
-    };
-
-    auto unused_items_get = [&](anm2::Type type)
-    {
-      if (!animation) return std::set<int>{};
-      if (type == anm2::LAYER) return anm2.layers_unused(*animation);
-      if (type == anm2::NULL_) return anm2.nulls_unused(*animation);
-      return std::set<int>{};
-    };
-
     auto item_context_menu = [&]()
     {
       ImGui::PushStyleVar(ImGuiStyleVar_WindowPadding, style.WindowPadding);
@@ -688,10 +673,7 @@ namespace anm2ed::imgui
           item_base_properties_open(type, id);
 
         if (ImGui::MenuItem(localize.get(BASIC_ADD), settings.shortcutAdd.c_str(), false, animation))
-        {
-          item_properties_reset();
-          propertiesPopup.open();
-        }
+          itemProperties.open();
 
         if (ImGui::MenuItem(localize.get(BASIC_REMOVE), settings.shortcutRemove.c_str(), false, item)) item_remove();
 
@@ -1086,10 +1068,7 @@ namespace anm2ed::imgui
         {
           shortcut(manager.chords[SHORTCUT_ADD]);
           if (ImGui::Button(localize.get(BASIC_ADD), widgetSize))
-          {
-            item_properties_reset();
-            propertiesPopup.open();
-          }
+            itemProperties.open();
           set_item_tooltip_shortcut(localize.get(TOOLTIP_ADD_ITEM), settings.shortcutAdd);
           ImGui::SameLine();
 
@@ -1922,189 +1901,7 @@ namespace anm2ed::imgui
     ImGui::PopStyleVar();
     ImGui::End();
 
-    propertiesPopup.trigger();
-
-    if (ImGui::BeginPopupModal(propertiesPopup.label(), &propertiesPopup.isOpen, ImGuiWindowFlags_NoResize))
-    {
-      auto item_properties_close = [&]()
-      {
-        item_properties_reset();
-        propertiesPopup.close();
-      };
-
-      auto& type = settings.timelineAddItemType;
-      auto& destination = settings.timelineAddItemDestination;
-      auto& source = settings.timelineAddItemSource;
-
-      auto footerSize = footer_size_get();
-      auto optionsSize = child_size_get(11);
-      auto itemsSize = ImVec2(0, ImGui::GetContentRegionAvail().y -
-                                     (optionsSize.y + footerSize.y + ImGui::GetStyle().ItemSpacing.y * 4));
-      if (ImGui::BeginChild("##Options", optionsSize, ImGuiChildFlags_Borders))
-      {
-        ImGui::SeparatorText(localize.get(LABEL_TYPE));
-
-        auto size = ImVec2(ImGui::GetContentRegionAvail().x * 0.5f, ImGui::GetFrameHeightWithSpacing());
-
-        if (ImGui::BeginChild("##Type 1", size))
-        {
-          ImGui::RadioButton(localize.get(LABEL_LAYER), &type, anm2::LAYER);
-          ImGui::SetItemTooltip("%s", localize.get(TOOLTIP_LAYER_TYPE));
-        }
-        ImGui::EndChild();
-
-        ImGui::SameLine();
-
-        if (ImGui::BeginChild("##Type 2", size))
-        {
-          ImGui::RadioButton(localize.get(LABEL_NULL), &type, anm2::NULL_);
-          ImGui::SetItemTooltip("%s", localize.get(TOOLTIP_NULL_TYPE));
-        }
-        ImGui::EndChild();
-
-        ImGui::SeparatorText(localize.get(LABEL_SOURCE));
-
-        if (ImGui::BeginChild("##Source 1", size))
-        {
-          ImGui::RadioButton(localize.get(LABEL_NEW), &source, source::NEW);
-          ImGui::SetItemTooltip("%s", localize.get(TOOLTIP_NEW_ITEM));
-        }
-        ImGui::EndChild();
-
-        ImGui::SameLine();
-
-        if (ImGui::BeginChild("##Source 2", size))
-        {
-          auto isUnusedItems = animation && !unused_items_get((anm2::Type)type).empty();
-          ImGui::BeginDisabled(!isUnusedItems);
-          ImGui::RadioButton(localize.get(LABEL_EXISTING), &source, source::EXISTING);
-          ImGui::EndDisabled();
-          ImGui::SetItemTooltip("%s", isUnusedItems ? localize.get(TOOLTIP_USE_EXISTING_ITEM)
-                                                    : localize.get(TOOLTIP_NO_UNUSED_ITEMS));
-        }
-        ImGui::EndChild();
-
-        ImGui::SeparatorText(localize.get(LABEL_DESTINATION));
-
-        if (ImGui::BeginChild("##Destination 1", size))
-        {
-          ImGui::RadioButton(localize.get(LABEL_ALL_ANIMATIONS), &destination, destination::ALL);
-          ImGui::SetItemTooltip("%s", localize.get(TOOLTIP_ITEM_ALL_ANIMATIONS));
-        }
-        ImGui::EndChild();
-
-        ImGui::SameLine();
-
-        if (ImGui::BeginChild("##Destination 2", size))
-        {
-          ImGui::RadioButton(localize.get(LABEL_THIS_ANIMATION), &destination, destination::THIS);
-          ImGui::SetItemTooltip("%s", localize.get(TOOLTIP_ITEM_THIS_ANIMATION));
-        }
-        ImGui::EndChild();
-
-        ImGui::SeparatorText(localize.get(LABEL_OPTIONS));
-
-        ImGui::BeginDisabled(source == source::EXISTING);
-        {
-          input_text_string(localize.get(BASIC_NAME), &addItemName);
-          ImGui::SetItemTooltip("%s", localize.get(TOOLTIP_ITEM_NAME));
-          if (type == anm2::LAYER)
-          {
-            combo_id_mapped(localize.get(LABEL_SPRITESHEET), &addItemSpritesheetID, document.spritesheet.ids,
-                            document.spritesheet.labels);
-            ImGui::SetItemTooltip("%s", localize.get(TOOLTIP_LAYER_SPRITESHEET));
-          }
-          else if (type == anm2::NULL_)
-          {
-            ImGui::Checkbox(localize.get(LABEL_RECT), &addItemIsShowRect);
-            ImGui::SetItemTooltip("%s", localize.get(TOOLTIP_NULL_RECT));
-          }
-        }
-        ImGui::EndDisabled();
-      }
-      ImGui::EndChild();
-
-      if (ImGui::BeginChild("##Items", itemsSize, ImGuiChildFlags_Borders))
-      {
-        if (animation && source == source::EXISTING)
-        {
-          auto unusedItems = unused_items_get((anm2::Type)type);
-          if (addItemID != -1 && !unusedItems.contains(addItemID)) addItemID = -1;
-
-          for (auto id : unusedItems)
-          {
-            auto isSelected = addItemID == id;
-
-            ImGui::PushID(id);
-
-            if (type == anm2::LAYER)
-            {
-              if (auto it = anm2.content.layers.find(id); it != anm2.content.layers.end())
-              {
-                auto& layer = it->second;
-                auto label = std::vformat(localize.get(FORMAT_LAYER),
-                                          std::make_format_args(id, layer.name, layer.spritesheetID));
-                if (ImGui::Selectable(label.c_str(), isSelected))
-                {
-                  addItemID = id;
-                  addItemSpritesheetID = layer.spritesheetID;
-                }
-              }
-            }
-            else if (type == anm2::NULL_)
-            {
-              if (auto it = anm2.content.nulls.find(id); it != anm2.content.nulls.end())
-              {
-                auto& null = it->second;
-                auto label = std::vformat(localize.get(FORMAT_NULL), std::make_format_args(id, null.name));
-                if (ImGui::Selectable(label.c_str(), isSelected))
-                {
-                  addItemID = id;
-                  addItemIsShowRect = null.isShowRect;
-                }
-              }
-            }
-
-            ImGui::PopID();
-          }
-        }
-      }
-      ImGui::EndChild();
-
-      auto widgetSize = widget_size_with_row_get(2);
-
-      ImGui::BeginDisabled(source == source::EXISTING && addItemID == -1);
-      shortcut(manager.chords[SHORTCUT_CONFIRM]);
-      if (ImGui::Button(localize.get(BASIC_ADD), widgetSize))
-      {
-        anm2::Reference addReference{};
-        int insertBeforeID = reference.itemType == anm2::LAYER ? reference.itemID : -1;
-
-        document.snapshot(localize.get(EDIT_ADD_ITEM));
-        if (type == anm2::LAYER)
-          addReference = anm2.layer_animation_add({reference.animationIndex, anm2::LAYER, addItemID}, insertBeforeID,
-                                                  addItemName, addItemSpritesheetID, (destination::Type)destination);
-        else if (type == anm2::NULL_)
-          addReference = anm2.null_animation_add({reference.animationIndex, anm2::NULL_, addItemID}, addItemName,
-                                                 addItemIsShowRect, (destination::Type)destination);
-
-        document.change(Document::ITEMS);
-
-        reference_set_item(addReference.itemType, addReference.itemID);
-
-        item_properties_close();
-      }
-      ImGui::EndDisabled();
-      ImGui::SetItemTooltip("%s", localize.get(TOOLTIP_ADD_ITEM));
-
-      ImGui::SameLine();
-
-      shortcut(manager.chords[SHORTCUT_CANCEL]);
-      if (ImGui::Button(localize.get(BASIC_CANCEL), widgetSize)) item_properties_close();
-      ImGui::SetItemTooltip("%s", localize.get(TOOLTIP_CANCEL_ADD_ITEM));
-
-      ImGui::EndPopup();
-    }
+    itemProperties.update(manager, settings, document, animation, reference, reference_set_item);
 
     bakePopup.trigger();
 
diff --git a/src/imgui/window/timeline.hpp b/src/imgui/window/timeline.hpp
index b97c57a..2ba736b 100644
--- a/src/imgui/window/timeline.hpp
+++ b/src/imgui/window/timeline.hpp
@@ -4,6 +4,7 @@
 
 #include "clipboard.hpp"
 #include "manager.hpp"
+#include "popup/item_properties.hpp"
 #include "resources.hpp"
 #include "settings.hpp"
 #include "strings.hpp"
@@ -26,12 +27,8 @@ namespace anm2ed::imgui
     bool isDragging{};
     bool isWindowHovered{};
     bool isHorizontalScroll{};
-    PopupHelper propertiesPopup{PopupHelper(LABEL_TIMELINE_PROPERTIES_POPUP, POPUP_NORMAL)};
+    popup::ItemProperties itemProperties{};
     PopupHelper bakePopup{PopupHelper(LABEL_TIMELINE_BAKE_POPUP, POPUP_SMALL_NO_HEIGHT)};
-    std::string addItemName{"New Item"};
-    bool addItemIsShowRect{};
-    int addItemID{-1};
-    int addItemSpritesheetID{-1};
     int hoveredTime{};
     anm2::Frame* draggedFrame{};
     anm2::Type draggedFrameType{};