diff --git a/res/layouts/pages/404.xml b/res/layouts/pages/404.xml
index 1912fc2f..c53262bc 100644
--- a/res/layouts/pages/404.xml
+++ b/res/layouts/pages/404.xml
@@ -1,4 +1,4 @@
 <panel size='400' padding='8' interval='8' color='0'>
-    <label context='menu'>@Page does not exists</label>
+    <label context='menu'>@Page not found</label>
     <button onclick='menu:back()'>@Back</button>
 </panel>
diff --git a/res/layouts/pages/add_packs.xml b/res/layouts/pages/add_packs.xml
deleted file mode 100644
index e70993a6..00000000
--- a/res/layouts/pages/add_packs.xml
+++ /dev/null
@@ -1,6 +0,0 @@
-<panel size='550' color='0' padding='8' interval='5'>
-    <panel id='packs_panel' size='540,10' color='0,0,0,50' max-length='400'>
-        <!-- content is generated in script -->
-    </panel>
-    <button onclick='menu:back()'>@Back</button>
-</panel>
diff --git a/res/layouts/pages/add_packs.xml.lua b/res/layouts/pages/add_packs.xml.lua
deleted file mode 100644
index c27697c3..00000000
--- a/res/layouts/pages/add_packs.xml.lua
+++ /dev/null
@@ -1,14 +0,0 @@
-function add_pack(packid, packinfo)
-    local callback = string.format('core.add_packs({%q})', packid)
-    packinfo.id = packid
-    packinfo.callback = callback
-    packinfo.icon = "gui/no_icon"
-    document.packs_panel:add(gui.template("pack", packinfo))
-end
-
-function on_open()
-    local packs = pack.get_available()
-    for i,id in ipairs(packs) do
-        add_pack(id, pack.get_info(id))
-    end
-end
diff --git a/res/layouts/pages/content.xml b/res/layouts/pages/content.xml
index 82037dfa..d070212d 100644
--- a/res/layouts/pages/content.xml
+++ b/res/layouts/pages/content.xml
@@ -1,7 +1,13 @@
-<panel size='550' color='0' padding='8' interval='5'>
-    <panel id='packs_panel' size='540,10' color='0,0,0,50' max-length='400'>
+<container size='767,454' color='#0F1E2DB2' padding='8' interval='5' context='menu'>
+    <panel id='packs_cur' pos='2' size='380,406' color='0' max-length='406'>
         <!-- content is generated in script -->
     </panel>
-    <button onclick='menu.page = "add_packs"'>@Add</button>
-    <button onclick='menu:back()'>@Back</button>
-</panel>
+    <panel id='packs_add' pos='385,2' size='380,406' color='0' max-length='406'>
+        <!-- content is generated in script -->
+    </panel>
+    <button id='apply_btn' pos='2,410' size='380,40' onclick='apply()'>@Apply</button>
+    <button pos='385,410' size='338,40' onclick='menu:back()'>@Cancel</button>
+    <image onclick='refresh()' interactive='true' src='gui/refresh' 
+        size='32' margin='7' gravity='bottom-right'
+        color='#FFFFFF80' hover-color='#FFFFFF10'/>
+</container>
diff --git a/res/layouts/pages/content.xml.lua b/res/layouts/pages/content.xml.lua
index e6c88c7c..c0edf7f9 100644
--- a/res/layouts/pages/content.xml.lua
+++ b/res/layouts/pages/content.xml.lua
@@ -1,19 +1,85 @@
-function add_pack(packid, packinfo)
-    local remover = ''
-    if packid ~= "base" then
-        remover = string.format('core.remove_packs({%q})', packid)
+function on_open()
+    refresh()
+end
+
+-- // FIXME: dependency checks
+add_packs = {}
+rem_packs = {}
+
+function apply()
+    core.reconfig_packs(add_packs, rem_packs)
+end
+
+function refresh_changes()
+    document.apply_btn.enabled = (#add_packs>0) or (#rem_packs>0)
+end
+
+function move_pack(id)
+    -- cancel pack addition
+    if table.has(add_packs, id) then
+        document["pack_"..id]:move_into(document.packs_add)
+        table.remove_value(add_packs, id)
+    -- cancel pack removal
+    elseif table.has(rem_packs, id) then
+        document["pack_"..id]:move_into(document.packs_cur)
+        table.remove_value(rem_packs, id)
+    -- add pack
+    elseif table.has(packs_installed, id) then
+        document["pack_"..id]:move_into(document.packs_add)
+        table.insert(rem_packs, id)
+    -- remove pack
+    else
+        document["pack_"..id]:move_into(document.packs_cur)
+        table.insert(add_packs, id)
     end
+    refresh_changes()
+end
+
+function place_pack(panel, packid, packinfo, callback)
+    packinfo.id = packid
+    callback = callback or ""
     if packinfo.has_indices then
         packid = packid.."*"
     end
-    packinfo.id = packid
-    packinfo.remover = remover
-    document.packs_panel:add(gui.template("pack", packinfo))
+    packinfo.id_verbose = packid
+    packinfo.callback = callback
+    panel:add(gui.template("pack", packinfo))
 end
 
-function on_open()
-    local packs = pack.get_installed()
-    for i,id in ipairs(packs) do
-        add_pack(id, pack.get_info(id))
+function refresh()
+    packs_installed = pack.get_installed()
+    packs_available = pack.get_available()
+    
+    local packs_cur = document.packs_cur
+    local packs_add = document.packs_add
+
+    packs_cur:clear()
+    packs_add:clear()
+    refresh_changes()
+
+    for i,id in ipairs(packs_installed) do
+        local packinfo = pack.get_info(id)
+        packinfo.index = i
+        callback = id ~= "base" and string.format('move_pack("%s")', id) or nil
+        place_pack(packs_cur, id, packinfo, callback)
+    end
+
+    for i,id in ipairs(packs_available) do
+        local packinfo = pack.get_info(id)
+        packinfo.index = i
+        callback = string.format('move_pack("%s")', id)
+        place_pack(packs_add, id, packinfo, callback)
+    end
+
+    -- apply packs movements
+    for i,id in ipairs(packs_installed) do
+        if table.has(rem_packs, id) then
+            document["pack_"..id]:move_into(packs_add)
+        end
+    end
+    for i,id in ipairs(packs_available) do
+        if table.has(add_packs, id) then
+            document["pack_"..id]:move_into(packs_cur)
+        end
     end
 end
diff --git a/res/layouts/templates/pack.xml b/res/layouts/templates/pack.xml
index 691c4173..ae637cc0 100644
--- a/res/layouts/templates/pack.xml
+++ b/res/layouts/templates/pack.xml
@@ -1,6 +1,6 @@
-<container onclick='%{callback}' size='540,80' color='#0F1E2DB2' hover-color='#0F1E2DF0'>
+<container id='pack_%{id}' onclick='%{callback}' size='540,80' color='#00000040' hover-color='#00000080' z-index="%{index}">
     <label color='#FFFFFF80' size='300,25' align='right' gravity='top-right'>
-        [%{id}]
+        [%{id_verbose}]
     </label>
     <label pos='78,6'>%{title}</label>
     <label if='%{creator}' color='#CCFFE5B2' size='300,20' align='right' 
@@ -10,9 +10,5 @@
     <label pos='80,28' color='#FFFFFFB2'>
         %{description}
     </label>
-    <button if='%{remover}' onclick='%{remover}' color='0' hover-color='#FFFFFF2B' 
-            gravity='center-right' margin='10' padding='0'>
-        <image src='gui/cross' size='32,32' color='#FFFFFF80'/>
-    </button>
-    <image pos='8,8' src='%{icon}' size='64'></image>
+    <image pos='8,8' src='%{icon}' size='64'/>
 </container>
diff --git a/res/scripts/stdlib.lua b/res/scripts/stdlib.lua
index faf85909..422a6edb 100644
--- a/res/scripts/stdlib.lua
+++ b/res/scripts/stdlib.lua
@@ -232,6 +232,37 @@ function session.reset_entry(name)
     session.entries[name] = nil
 end
 
+function timeit(func, ...)
+    local tm = time.uptime()
+    func(...)
+    print("[time mcs]", (time.uptime()-tm) * 1000000)
+end
+
+function table.has(t, x)
+    for i,v in ipairs(t) do
+        if v == x then
+            return true
+        end
+    end
+    return false
+end
+
+function table.index(t, x)
+    for i,v in ipairs(t) do
+        if v == x then
+            return i
+        end
+    end
+    return -1
+end
+
+function table.remove_value(t, x)
+    local index = table.index(t, x)
+    if index ~= -1 then
+        table.remove(t, index)
+    end
+end
+
 -- Deprecated functions
 block_index = block.index
 block_name = block.name
diff --git a/res/texts/de_DE.txt b/res/texts/de_DE.txt
index ce6b21ec..0251f395 100644
--- a/res/texts/de_DE.txt
+++ b/res/texts/de_DE.txt
@@ -13,44 +13,44 @@ error.dependency-not-found=Die verwendete Abhängigkeit wurde nicht gefunden
 pack.remove-confirm=Alle vom Paket bereitgestellten Inhalte (dauerhaft) aus der Welt löschen?
 
 # Меню
+menu.Apply=Anwenden
+menu.Audio=Klang
+menu.Back to Main Menu=Zurück zum Menü
+menu.Content Error=Inhaltsfehler
+menu.Content=Inhalt
+menu.Continue=Weitermachen
+menu.Controls=Kontrolle
+menu.Create World=Erschaffe eine Welt
+menu.missing-content=Fehlender Inhalt!
 menu.New World=Neue Welt
 menu.Quit=Ausfahrt
-menu.Continue=Weitermachen
 menu.Save and Quit to Menu=Speichern und zum Menü zurückkehren
-menu.missing-content=Fehlender Inhalt!
-menu.Content Error=Inhaltsfehler
-menu.Controls=Kontrolle
-menu.Back to Main Menu=Zurück zum Menü
 menu.Settings=Einstellungen
-menu.Content=Inhalt
-menu.Audio=Klang
+
 world.Seed=Mais
 world.Name=Name
-
 world.World generator=Weltgenerator
 world.generators.default=Normal
 world.generators.flat=Wohnung
-menu.Create World=Erschaffe eine Welt
-
+world.Create World=Welt Erschaffen
 world.convert-request=Es gibt Änderungen in den Indizes! Die Welt bekehren?
 world.delete-confirm=Die Welt dauerhaft löschen?
 
 # Настройки
+settings.Ambient=Hintergrund
+settings.Backlight=Hintergrundbeleuchtung
+settings.Camera Shaking=Wackelnde Kamera
+settings.Fog Curve=Nebelkurve
+settings.FOV=Sichtlinie
+settings.Language=Sprache
 settings.Load Distance=Ladeentfernung
 settings.Load Speed=Download-Geschwindigkeit
-settings.Fog Curve=Nebelkurve
-settings.Backlight=Hintergrundbeleuchtung
-settings.V-Sync=Vertikale Synchronisation
-settings.Camera Shaking=Wackelnde Kamera
 settings.Master Volume=Allgemeine Lautstärke
+settings.Mouse Sensitivity=Maus-Empfindlichkeit
+settings.Music=Musik
 settings.Regular Sounds=Normale Geräusche
 settings.UI Sounds=Interface-Sounds
-settings.Ambient=Hintergrund
-settings.Music=Musik
-
-settings.FOV=Sichtlinie
-settings.Mouse Sensitivity=Maus-Empfindlichkeit
-settings.Language=Sprache
+settings.V-Sync=Vertikale Synchronisation
 
 # Управление
 movement.forward=Vorwärts
diff --git a/res/texts/pl_PL.txt b/res/texts/pl_PL.txt
index aebdab1c..39f1a1a7 100644
--- a/res/texts/pl_PL.txt
+++ b/res/texts/pl_PL.txt
@@ -5,38 +5,53 @@ Ok=OK
 Cancel=Anulowanie
 Back=Powrót
 Continue=Kontynuacja
+Add=Dodać
+Converting world...=Konwersja świata w toku...
 
 error.pack-not-found=Nie udało się znaleźć pakietu
 
 # Menu
-menu.New World=Nowy Świat
-menu.Quit=Wyjście
-menu.Continue=Kontynuacja
-menu.Save and Quit to Menu=Zapisz i wyjdź do menu
-menu.missing-content=Brak treści!
-menu.Controls=Zarządzanie
+menu.Apply=Zastosować
+menu.Audio=Dźwięki
 menu.Back to Main Menu=Powrót do menu
-menu.Settings=Ustawienia
 menu.Content=Treść
+menu.Continue=Kontynuacja
+menu.Controls=Zarządzanie
+menu.Graphics=Grafika
+menu.Create World=Stwórz świat
+menu.missing-content=Brakująca treść!
+menu.New World=Nowy Świat
+menu.Page not found=Strona nie znaleziona
+menu.Quit=Wyjście
+menu.Save and Quit to Menu=Zapisz i wyjdź do menu
+menu.Settings=Ustawienia
+
 world.Seed=Ziarno
 world.Name=Nazwa
-menu.Create World=Stwórz świat
-
 world.World generator=Generator światła
 world.generators.default=Ekstremalne
 world.generators.flat=Mieszkanie
+world.Create World=Stwórz świat
 world.convert-request=Szykują się zmiany w indeksach! Przekształcić świat?
+world.delete-confirm=Trwale usunąć świat?
 
 # Ustawienia
+settings.Ambient=Tło
+settings.Backlight=Podświetlenie
+settings.Camera Shaking=Drżąca kamera
+settings.Fog Curve=Krzywa mgły
+settings.FOV=Wzrok
+settings.Fullscreen=Pełny ekran
+settings.Gamma=Gamma
+settings.Language=Język
 settings.Load Distance=Odległość ładowania
 settings.Load Speed=Prędkość pobierania
-settings.Fog Curve=Krzywa mgły
-settings.Backlight=Podświetlenie
-settings.V-Sync=Synchronizacja pionowa
-
-settings.FOV=Wzrok
+settings.Master Volume=Głośność główna
 settings.Mouse Sensitivity=Wrażliwość myszy
-settings.Language=Język
+settings.Music=Muzyka
+settings.Regular Sounds=Normalne dźwięki
+settings.UI Sounds=Dźwięki interfejsu
+settings.V-Sync=Synchronizacja pionowa
 
 # Zarządzanie
 movement.forward=Naprzód
diff --git a/res/texts/ru_RU.txt b/res/texts/ru_RU.txt
index cd57751a..04ee4e69 100644
--- a/res/texts/ru_RU.txt
+++ b/res/texts/ru_RU.txt
@@ -13,48 +13,47 @@ error.dependency-not-found=Используемая зависимость не
 pack.remove-confirm=Удалить весь поставляемый паком/паками контент из мира (безвозвратно)?
 
 # Меню
-menu.New World=Новый Мир
-menu.Quit=Выход
-menu.Continue=Продолжить
-menu.Save and Quit to Menu=Сохранить и Выйти в Меню
-menu.missing-content=Отсутствует Контент!
-menu.Page does not exists=Страница не существует
+menu.Apply=Применить
+menu.Audio=Звук
+menu.Back to Main Menu=Вернуться в Меню
 menu.Content Error=Ошибка Контента
+menu.Content=Контент
+menu.Continue=Продолжить
 menu.Controls=Управление
 menu.Graphics=Графика
-menu.Back to Main Menu=Вернуться в Меню
+menu.missing-content=Отсутствует Контент!
+menu.New World=Новый Мир
+menu.Page not found=Страница не найдена
+menu.Quit=Выход
+menu.Save and Quit to Menu=Сохранить и Выйти в Меню
 menu.Settings=Настройки
-menu.Content=Контент
-menu.Audio=Звук
+
 world.Seed=Зерно
 world.Name=Название
-
 world.World generator=Генератор мира
 world.generators.default=Обычный
 world.generators.flat=Плоский
 world.Create World=Создать Мир
-
 world.convert-request=Есть изменения в индексах! Конвертировать мир?
 world.delete-confirm=Удалить мир безвозвратно?
 
 # Настройки
+settings.Ambient=Фон
+settings.Backlight=Подсветка
+settings.Camera Shaking=Тряска Камеры
+settings.Fog Curve=Кривая Тумана
+settings.FOV=Поле Зрения
+settings.Fullscreen=Полный экран
+settings.Gamma=Гамма
+settings.Language=Язык
 settings.Load Distance=Дистанция Загрузки
 settings.Load Speed=Скорость Загрузки
-settings.Fog Curve=Кривая Тумана
-settings.Backlight=Подсветка
-settings.Gamma=Гамма
-settings.Fullscreen=Полноэкранный
-settings.V-Sync=Вертикальная Синхронизация
-settings.Camera Shaking=Тряска Камеры
 settings.Master Volume=Общая Громкость
+settings.Mouse Sensitivity=Чувствительность Мыши
+settings.Music=Музыка
 settings.Regular Sounds=Обычные Звуки
 settings.UI Sounds=Звуки Интерфейса
-settings.Ambient=Фон
-settings.Music=Музыка
-
-settings.FOV=Поле Зрения
-settings.Mouse Sensitivity=Чувствительность Мыши
-settings.Language=Язык
+settings.V-Sync=Вертикальная Синхронизация
 
 # Управление
 movement.forward=Вперёд
diff --git a/res/texts/uk_UA.txt b/res/texts/uk_UA.txt
index 4030d650..175c172f 100644
--- a/res/texts/uk_UA.txt
+++ b/res/texts/uk_UA.txt
@@ -5,19 +5,26 @@ Ok=Гаразд
 Cancel=Скасувати
 Back=Назад
 Continue=Продовжити
+Add=Додати
+Converting world...=Виконується конвертація світу...
 
 error.pack-not-found=Не вдалося знайти пакет
 
 # Меню
-menu.New World=Новий Світ
-menu.Quit=Вихід
-menu.Continue=Продовжити
-menu.Save and Quit to Menu=Зберегти і Вийти в Меню
-menu.missing-content=Відсутній Контент!
-menu.Controls=Керування
+menu.Apply=Застосувати
+menu.Audio=Звук
 menu.Back to Main Menu=Повернутися до Меню
-menu.Settings=Налаштування
+menu.Content Error=Помилка Контенту
 menu.Content=Контент
+menu.Continue=Продовжити
+menu.Controls=Керування
+menu.Graphics=Графіка
+menu.missing-content=Відсутній Контент!
+menu.New World=Новий Світ
+menu.Page not found=Сторінка не знайдена
+menu.Quit=Вихід
+menu.Save and Quit to Menu=Зберегти і Вийти в Меню
+menu.Settings=Налаштування
 world.Seed=Зерно
 world.Name=Назва
 menu.Create World=Створити Світ
@@ -28,15 +35,22 @@ world.generators.flat=Плоскі
 world.convert-request=Є зміни в індексах! Конвертувати світ?
 
 # Налаштування
+settings.Ambient=Фон
+settings.Backlight=Підсвічування
+settings.Camera Shaking=Тряска Камери
+settings.Fog Curve=Крива Туману
+settings.FOV=Поле зору
+settings.Fullscreen=Повний екран
+settings.Gamma=Гамма
+settings.Language=Мова
 settings.Load Distance=Дистанція Завантаження
 settings.Load Speed=Швидкість Завантаження
-settings.Fog Curve=Крива Туману
-settings.Backlight=Підсвічування
-settings.V-Sync=Вертикальна Синхронізація
-
-settings.FOV=Поле зору
+settings.Master Volume=Загальна Гучність
 settings.Mouse Sensitivity=Чутливість Миші
-settings.Language=Мова
+settings.Music=Музика
+settings.Regular Sounds=Звичайні Звуки
+settings.UI Sounds=Звуки інтерфейсу
+settings.V-Sync=Вертикальна Синхронізація
 
 # Керування
 movement.forward=Уперед
diff --git a/res/textures/gui/circle.png b/res/textures/gui/circle.png
new file mode 100644
index 00000000..b82a72ee
Binary files /dev/null and b/res/textures/gui/circle.png differ
diff --git a/res/textures/gui/cross.png b/res/textures/gui/cross.png
index 2656b8bc..021a5ef1 100644
Binary files a/res/textures/gui/cross.png and b/res/textures/gui/cross.png differ
diff --git a/res/textures/gui/refresh.png b/res/textures/gui/refresh.png
new file mode 100644
index 00000000..ffbbb387
Binary files /dev/null and b/res/textures/gui/refresh.png differ
diff --git a/src/assets/AssetsLoader.cpp b/src/assets/AssetsLoader.cpp
index 0c8368ba..d626582e 100644
--- a/src/assets/AssetsLoader.cpp
+++ b/src/assets/AssetsLoader.cpp
@@ -184,6 +184,7 @@ void AssetsLoader::addDefaults(AssetsLoader& loader, const Content* content) {
     loader.add(AssetType::texture, TEXTURES_FOLDER+"/gui/warning", "gui/warning");
     loader.add(AssetType::texture, TEXTURES_FOLDER+"/gui/error", "gui/error");
     loader.add(AssetType::texture, TEXTURES_FOLDER+"/gui/cross", "gui/cross");
+    loader.add(AssetType::texture, TEXTURES_FOLDER+"/gui/refresh", "gui/refresh");
     if (content) {
         loader.processPreloadConfigs(content);
 
diff --git a/src/frontend/hud.cpp b/src/frontend/hud.cpp
index e301d5b5..f067989e 100644
--- a/src/frontend/hud.cpp
+++ b/src/frontend/hud.cpp
@@ -203,6 +203,9 @@ void Hud::processInput(bool visible) {
             setPause(true);
         }
     }
+    if (!Window::isFocused() && !pause && !isInventoryOpen()) {
+        setPause(true);
+    }
 
     if (!pause && visible && Events::jactive(BIND_HUD_INVENTORY)) {
         if (inventoryOpen) {
diff --git a/src/graphics/ui/elements/Container.cpp b/src/graphics/ui/elements/Container.cpp
index 579ae8d9..93dead99 100644
--- a/src/graphics/ui/elements/Container.cpp
+++ b/src/graphics/ui/elements/Container.cpp
@@ -125,6 +125,14 @@ void Container::remove(std::shared_ptr<UINode> selected) {
     refresh();
 }
 
+void Container::clear() {
+    for (auto node : nodes) {
+        node->setParent(nullptr);
+    }
+    nodes.clear();
+    refresh();
+}
+
 void Container::listenInterval(float interval, ontimeout callback, int repeat) {
     intervalEvents.push_back({callback, interval, 0.0f, repeat});
 }
diff --git a/src/graphics/ui/elements/Container.hpp b/src/graphics/ui/elements/Container.hpp
index 96a29491..8aa38b2f 100644
--- a/src/graphics/ui/elements/Container.hpp
+++ b/src/graphics/ui/elements/Container.hpp
@@ -24,6 +24,7 @@ namespace gui {
         virtual std::shared_ptr<UINode> getAt(glm::vec2 pos, std::shared_ptr<UINode> self) override;
         virtual void add(std::shared_ptr<UINode> node);
         virtual void add(std::shared_ptr<UINode> node, glm::vec2 pos);
+        virtual void clear();
         virtual void remove(std::shared_ptr<UINode> node);
         virtual void scrolled(int value) override;
         virtual void setScrollable(bool flag);
diff --git a/src/graphics/ui/elements/Image.cpp b/src/graphics/ui/elements/Image.cpp
index d337a2c4..0b2d4945 100644
--- a/src/graphics/ui/elements/Image.cpp
+++ b/src/graphics/ui/elements/Image.cpp
@@ -22,9 +22,13 @@ void Image::draw(const DrawContext* pctx, Assets* assets) {
         setSize(glm::vec2(texture->getWidth(), texture->getHeight()));
     }
     batch->texture(texture);
-    batch->setColor(color);
+    if (enabled) {
+        batch->setColor(isPressed() ? pressedColor : (hover ? hoverColor : color));
+    } else {
+        batch->setColor({color.r, color.g, color.b, color.a * 0.5f});
+    }
     batch->rect(pos.x, pos.y, size.x, size.y, 
-                0, 0, 0, UVRegion(), false, true, color);
+                0, 0, 0, UVRegion(), false, true, batch->getColor());
 }
 
 void Image::setAutoResize(bool flag) {
diff --git a/src/graphics/ui/elements/Panel.cpp b/src/graphics/ui/elements/Panel.cpp
index 2cf1c432..036161ed 100644
--- a/src/graphics/ui/elements/Panel.cpp
+++ b/src/graphics/ui/elements/Panel.cpp
@@ -52,6 +52,10 @@ void Panel::add(std::shared_ptr<UINode> node) {
 
 void Panel::refresh() {
     UINode::refresh();
+    std::stable_sort(nodes.begin(), nodes.end(), [](auto a, auto b) {
+        return a->getZIndex() < b->getZIndex();
+    });
+
     float x = padding.x;
     float y = padding.y;
     glm::vec2 size = getSize();
diff --git a/src/graphics/ui/elements/UINode.cpp b/src/graphics/ui/elements/UINode.cpp
index ca08513e..cd85e265 100644
--- a/src/graphics/ui/elements/UINode.cpp
+++ b/src/graphics/ui/elements/UINode.cpp
@@ -198,7 +198,18 @@ int UINode::getZIndex() const {
     return zindex;
 }
 
-void UINode::lock() {
+void UINode::moveInto(
+    std::shared_ptr<UINode> node,
+    std::shared_ptr<Container> dest
+) {
+    auto parent = node->getParent();
+    if (auto container = dynamic_cast<Container*>(parent)) {
+        container->remove(node);
+    }
+    if (parent) {
+        parent->scrolled(0);
+    }
+    dest->add(node);
 }
 
 vec2supplier UINode::getPositionFunc() const {
diff --git a/src/graphics/ui/elements/UINode.hpp b/src/graphics/ui/elements/UINode.hpp
index cc2abf68..236b968d 100644
--- a/src/graphics/ui/elements/UINode.hpp
+++ b/src/graphics/ui/elements/UINode.hpp
@@ -17,6 +17,7 @@ class Assets;
 namespace gui {
     class UINode;
     class GUI;
+    class Container;
 
     using onaction = std::function<void(GUI*)>;
     using onnumberchange = std::function<void(GUI*, double)>;
@@ -188,7 +189,10 @@ namespace gui {
                 parent->fullRefresh();
             }
         };
-        virtual void lock();
+        static void moveInto(
+            std::shared_ptr<UINode> node,
+            std::shared_ptr<Container> dest
+        );
 
         virtual vec2supplier getPositionFunc() const;
         virtual void setPositionFunc(vec2supplier);
diff --git a/src/logic/EngineController.cpp b/src/logic/EngineController.cpp
index 889498a6..79670eb1 100644
--- a/src/logic/EngineController.cpp
+++ b/src/logic/EngineController.cpp
@@ -217,8 +217,9 @@ void EngineController::reopenWorld(World* world) {
     openWorld(wname, true);
 }
 
-void EngineController::removePacks(
+void EngineController::reconfigPacks(
     LevelController* controller,
+    std::vector<std::string> packsToAdd,
     std::vector<std::string> packsToRemove
 ) {
     auto content = engine->getContent();
@@ -242,6 +243,9 @@ void EngineController::removePacks(
         manager.scan();
 
         auto names = PacksManager::getNames(world->getPacks());
+        for (const auto& id : packsToAdd) {
+            names.push_back(id);
+        }
         for (const auto& id : packsToRemove) {
             manager.exclude(id);
             names.erase(std::find(names.begin(), names.end(), id));
@@ -262,31 +266,3 @@ void EngineController::removePacks(
         removeFunc();
     }
 }
-
-void EngineController::addPacks(
-    LevelController* controller,
-    std::vector<std::string> packs
-) {
-    auto level = controller->getLevel();
-    auto gui = engine->getGUI();
-    auto world = level->getWorld();
-    auto new_packs = PacksManager::getNames(world->getPacks());
-    for (auto& id : packs) {
-        new_packs.push_back(id);
-    }
-
-    auto manager = engine->createPacksManager(world->wfile->getFolder());
-    manager.scan();
-    try {
-        new_packs = manager.assembly(new_packs);
-    } catch (const contentpack_error& err) {
-        guiutil::alert(
-            gui, langs::get(L"error.dependency-not-found")+
-            L": "+util::str2wstr_utf8(err.getPackId())
-        );
-        return;
-    }
-    world->wfile->writePacks(manager.getAll(new_packs));
-    controller->saveWorld();
-    reopenWorld(world);
-}
diff --git a/src/logic/EngineController.hpp b/src/logic/EngineController.hpp
index b2aebee0..b1041366 100644
--- a/src/logic/EngineController.hpp
+++ b/src/logic/EngineController.hpp
@@ -22,14 +22,10 @@ public:
     /// @param name world name
     void deleteWorld(std::string name);
 
-    void removePacks(
-        LevelController* controller, 
-        std::vector<std::string> packs
-    );
-
-    void addPacks(
+    void reconfigPacks(
         LevelController* controller,
-        std::vector<std::string> packs
+        std::vector<std::string> packsToAdd,
+        std::vector<std::string> packsToRemove
     );
 
     void createWorld(
diff --git a/src/logic/scripting/lua/libcore.cpp b/src/logic/scripting/lua/libcore.cpp
index 4cd90244..c6f262a5 100644
--- a/src/logic/scripting/lua/libcore.cpp
+++ b/src/logic/scripting/lua/libcore.cpp
@@ -8,6 +8,7 @@
 #include "../../../frontend/screens/MenuScreen.hpp"
 #include "../../../logic/LevelController.h"
 #include "../../../logic/EngineController.hpp"
+#include "../../../world/Level.h"
 #include "../../../window/Events.h"
 #include "../../../window/Window.h"
 #include "../../../world/WorldGenerators.h"
@@ -37,6 +38,12 @@ static int l_open_world(lua_State* L) {
     return 0;
 }
 
+static int l_reopen_world(lua_State* L) {
+    auto controller = scripting::engine->getController();
+    controller->reopenWorld(scripting::level->getWorld());
+    return 0;
+}
+
 static int l_close_world(lua_State* L) {
     if (scripting::controller == nullptr) {
         luaL_error(L, "no world open");
@@ -59,35 +66,30 @@ static int l_delete_world(lua_State* L) {
     return 0;
 }
 
-static int l_remove_packs(lua_State* L) {
+static int l_reconfig_packs(lua_State* L) {
     if (!lua_istable(L, 1)) {
-        luaL_error(L, "strings array expected as an argument");
+        luaL_error(L, "strings array expected as the first argument");
     }
-    std::vector<std::string> packs;
-    int len = lua_objlen(L, 1);
-    for (int i = 0; i < len; i++) {
-        lua_rawgeti(L, -1, i+1);
-        packs.push_back(lua_tostring(L, -1));
+    if (!lua_istable(L, 2)) {
+        luaL_error(L, "strings array expected as the second argument");
+    }
+    std::vector<std::string> addPacks;
+    int addLen = lua_objlen(L, 1);
+    for (int i = 0; i < addLen; i++) {
+        lua_rawgeti(L, 1, i+1);
+        addPacks.push_back(lua_tostring(L, -1));
         lua_pop(L, 1);
     }
-    auto controller = scripting::engine->getController();
-    controller->removePacks(scripting::controller, packs);
-    return 0;
-}
 
-static int l_add_packs(lua_State* L) {
-    if (!lua_istable(L, 1)) {
-        luaL_error(L, "strings array expected as an argument");
-    }
-    std::vector<std::string> packs;
-    int len = lua_objlen(L, 1);
-    for (int i = 0; i < len; i++) {
-        lua_rawgeti(L, -1, i+1);
-        packs.push_back(lua_tostring(L, -1));
+    std::vector<std::string> remPacks;
+    int remLen = lua_objlen(L, 2);
+    for (int i = 0; i < remLen; i++) {
+        lua_rawgeti(L, 2, i+1);
+        remPacks.push_back(lua_tostring(L, -1));
         lua_pop(L, 1);
     }
     auto controller = scripting::engine->getController();
-    controller->addPacks(scripting::controller, packs);
+    controller->reconfigPacks(scripting::controller, addPacks, remPacks);
     return 0;
 }
 
@@ -174,10 +176,10 @@ static int l_get_generators(lua_State* L) {
 const luaL_Reg corelib [] = {
     {"new_world", lua_wrap_errors<l_new_world>},
     {"open_world", lua_wrap_errors<l_open_world>},
+    {"reopen_world", lua_wrap_errors<l_reopen_world>},
     {"close_world", lua_wrap_errors<l_close_world>},
     {"delete_world", lua_wrap_errors<l_delete_world>},
-    {"add_packs", lua_wrap_errors<l_add_packs>},
-    {"remove_packs", lua_wrap_errors<l_remove_packs>},
+    {"reconfig_packs", lua_wrap_errors<l_reconfig_packs>},
     {"get_bindings", lua_wrap_errors<l_get_bindings>},
     {"get_setting", lua_wrap_errors<l_get_setting>},
     {"set_setting", lua_wrap_errors<l_set_setting>},
diff --git a/src/logic/scripting/lua/libgui.cpp b/src/logic/scripting/lua/libgui.cpp
index 82acf228..6a093da3 100644
--- a/src/logic/scripting/lua/libgui.cpp
+++ b/src/logic/scripting/lua/libgui.cpp
@@ -27,7 +27,7 @@ using namespace gui;
 
 struct DocumentNode {
     UiDocument* document;
-    UINode* node;
+    std::shared_ptr<UINode> node;
 };
 
 static DocumentNode getDocumentNode(lua_State* L, const std::string& name, const std::string& nodeName) {
@@ -39,7 +39,7 @@ static DocumentNode getDocumentNode(lua_State* L, const std::string& name, const
     if (node == nullptr) {
         luaL_error(L, "document '%s' has no element with id '%s'", name.c_str(), nodeName.c_str());
     }
-    return {doc, node.get()};
+    return {doc, node};
 }
 
 static bool getattr(lua_State* L, TrackBar* bar, const std::string& attr) {
@@ -137,9 +137,9 @@ static bool getattr(lua_State* L, TextBox* box, const std::string& attr) {
     return false;
 }
 
-static DocumentNode getDocumentNode(lua_State* L) {
-    lua_getfield(L, 1, "docname");
-    lua_getfield(L, 1, "name");
+static DocumentNode getDocumentNode(lua_State* L, int idx=1) {
+    lua_getfield(L, idx, "docname");
+    lua_getfield(L, idx, "name");
     auto docname = lua_tostring(L, -2);
     auto name = lua_tostring(L, -1);
     auto node = getDocumentNode(L, docname, name);
@@ -149,14 +149,14 @@ static DocumentNode getDocumentNode(lua_State* L) {
 
 static int menu_back(lua_State* L) {
     auto node = getDocumentNode(L);
-    auto menu = dynamic_cast<Menu*>(node.node);
+    auto menu = dynamic_cast<Menu*>(node.node.get());
     menu->back();
     return 0;
 }
 
 static int menu_reset(lua_State* L) {
     auto node = getDocumentNode(L);
-    auto menu = dynamic_cast<Menu*>(node.node);
+    auto menu = dynamic_cast<Menu*>(node.node.get());
     menu->reset();
     return 0;
 }
@@ -249,7 +249,7 @@ static bool setattr(lua_State* L, InventoryView* view, const std::string& attr)
 
 static int container_add(lua_State* L) {
     auto docnode = getDocumentNode(L);
-    auto node = dynamic_cast<Container*>(docnode.node);
+    auto node = dynamic_cast<Container*>(docnode.node.get());
     auto xmlsrc = lua_tostring(L, 2);
     try {
         auto subnode = guiutil::create(xmlsrc, docnode.document->getEnvironment());
@@ -261,6 +261,14 @@ static int container_add(lua_State* L) {
     return 0;
 }
 
+static int container_clear(lua_State* L) {
+    auto node = getDocumentNode(L, 1);
+    if (auto container = std::dynamic_pointer_cast<Container>(node.node)) {
+        container->clear();
+    }
+    return 0;
+}
+
 static bool getattr(lua_State* L, Container* container, const std::string& attr) {
     if (container == nullptr)
         return false;
@@ -268,6 +276,9 @@ static bool getattr(lua_State* L, Container* container, const std::string& attr)
     if (attr == "add") {
         lua_pushcfunction(L, container_add);
         return true;
+    } else if (attr == "clear") {
+        lua_pushcfunction(L, container_clear);
+        return true;
     }
     return false;
 }
@@ -283,6 +294,13 @@ static bool getattr(lua_State* L, InventoryView* inventory, const std::string& a
     return false;
 }
 
+static int uinode_move_into(lua_State* L) {
+    auto node = getDocumentNode(L, 1);
+    auto dest = getDocumentNode(L, 2);
+    UINode::moveInto(node.node, std::dynamic_pointer_cast<Container>(dest.node));
+    return 0;
+}
+
 static int l_gui_getattr(lua_State* L) {
     auto docname = lua_tostring(L, 1);
     auto element = lua_tostring(L, 2);
@@ -307,23 +325,26 @@ static int l_gui_getattr(lua_State* L) {
     } else if (attr == "enabled") {
         lua_pushboolean(L, node->isEnabled());
         return 1;
+    } else if (attr == "move_into") {
+        lua_pushcfunction(L, uinode_move_into);
+        return 1;
     }
 
-    if (getattr(L, dynamic_cast<Container*>(node), attr))
+    if (getattr(L, dynamic_cast<Container*>(node.get()), attr))
         return 1;
-    if (getattr(L, dynamic_cast<Button*>(node), attr))
+    if (getattr(L, dynamic_cast<Button*>(node.get()), attr))
         return 1;
-    if (getattr(L, dynamic_cast<Label*>(node), attr))
+    if (getattr(L, dynamic_cast<Label*>(node.get()), attr))
         return 1;
-    if (getattr(L, dynamic_cast<TextBox*>(node), attr))
+    if (getattr(L, dynamic_cast<TextBox*>(node.get()), attr))
         return 1;
-    if (getattr(L, dynamic_cast<TrackBar*>(node), attr))
+    if (getattr(L, dynamic_cast<TrackBar*>(node.get()), attr))
         return 1;
-    if (getattr(L, dynamic_cast<FullCheckBox*>(node), attr))
+    if (getattr(L, dynamic_cast<FullCheckBox*>(node.get()), attr))
         return 1;
-    if (getattr(L, dynamic_cast<Menu*>(node), attr))
+    if (getattr(L, dynamic_cast<Menu*>(node.get()), attr))
         return 1;
-    if (getattr(L, dynamic_cast<InventoryView*>(node), attr))
+    if (getattr(L, dynamic_cast<InventoryView*>(node.get()), attr))
         return 1;
 
     return 0;
@@ -356,19 +377,19 @@ static int l_gui_setattr(lua_State* L) {
     } else if (attr == "enabled") {
         node->setEnabled(lua_toboolean(L, 4));
     } else {
-        if (setattr(L, dynamic_cast<Button*>(node), attr))
+        if (setattr(L, dynamic_cast<Button*>(node.get()), attr))
             return 0;
-        if (setattr(L, dynamic_cast<Label*>(node), attr))
+        if (setattr(L, dynamic_cast<Label*>(node.get()), attr))
             return 0;
-        if (setattr(L, dynamic_cast<TextBox*>(node), attr))
+        if (setattr(L, dynamic_cast<TextBox*>(node.get()), attr))
             return 0;
-        if (setattr(L, dynamic_cast<TrackBar*>(node), attr))
+        if (setattr(L, dynamic_cast<TrackBar*>(node.get()), attr))
             return 0;
-        if (setattr(L, dynamic_cast<FullCheckBox*>(node), attr))
+        if (setattr(L, dynamic_cast<FullCheckBox*>(node.get()), attr))
             return 0;
-        if (setattr(L, dynamic_cast<Menu*>(node), attr))
+        if (setattr(L, dynamic_cast<Menu*>(node.get()), attr))
             return 0;
-        if (setattr(L, dynamic_cast<InventoryView*>(node), attr))
+        if (setattr(L, dynamic_cast<InventoryView*>(node.get()), attr))
             return 0;
     }
     return 0;
diff --git a/src/settings.h b/src/settings.h
index cad7934e..28e3b780 100644
--- a/src/settings.h
+++ b/src/settings.h
@@ -61,7 +61,7 @@ struct GraphicsSettings {
     /// @brief Enable blocks backlight to prevent complete darkness
     FlagSetting backlight {true};
     /// @brief Enable chunks frustum culling
-    FlagSetting frustumCulling {true}; // redutant?
+    FlagSetting frustumCulling {true};
     IntegerSetting skyboxResolution {64 + 32, 64, 128};
 };