diff --git a/res/layouts/process.xml b/res/layouts/process.xml
new file mode 100644
index 00000000..ccf631d8
--- /dev/null
+++ b/res/layouts/process.xml
@@ -0,0 +1,4 @@
+<panel size='400' padding='8' interval='1' color='#00000080'>
+    <label id='title_label'>???</label>
+    <label id='progress_label'>-</label>
+</panel>
diff --git a/res/layouts/process.xml.lua b/res/layouts/process.xml.lua
new file mode 100644
index 00000000..44e640e8
--- /dev/null
+++ b/res/layouts/process.xml.lua
@@ -0,0 +1,10 @@
+function on_progress(done, total)
+    local progress = done / total
+    document.progress_label.text = string.format(
+        "%s/%s (%s%%)", done, total, math.floor(progress*100)
+    )
+end
+
+function on_open(title)
+    document.title_label.text = title
+end
diff --git a/src/engine.cpp b/src/engine.cpp
index 3fbd1ed6..b6985ac2 100644
--- a/src/engine.cpp
+++ b/src/engine.cpp
@@ -227,11 +227,7 @@ void Engine::loadAssets() {
             }
         }
     }
-    if (assets) {
-        assets->extend(*new_assets);
-    } else {
-        assets.reset(new_assets.release());
-    }
+    assets.reset(new_assets.release());
 }
 
 void Engine::loadContent() {
diff --git a/src/frontend/UiDocument.h b/src/frontend/UiDocument.h
index b71a1747..57d0b8c2 100644
--- a/src/frontend/UiDocument.h
+++ b/src/frontend/UiDocument.h
@@ -16,6 +16,7 @@ namespace gui {
 
 struct uidocscript {
     bool onopen : 1;
+    bool onprogress : 1;
     bool onclose : 1;
 };
 
diff --git a/src/frontend/menu.cpp b/src/frontend/menu.cpp
index b5dea9ca..7c957601 100644
--- a/src/frontend/menu.cpp
+++ b/src/frontend/menu.cpp
@@ -49,7 +49,7 @@ void menus::create_menus(Engine* engine) {
     });
 }
 
-void menus::show(Engine* engine, const std::string& name, std::vector<std::unique_ptr<dynamic::Value>> args) {
+UiDocument* menus::show(Engine* engine, const std::string& name, std::vector<std::unique_ptr<dynamic::Value>> args) {
     auto menu = engine->getGUI()->getMenu();
     auto file = engine->getResPaths()->find("layouts/"+name+".xml");
     auto fullname = "core:layouts/"+name;
@@ -59,35 +59,23 @@ void menus::show(Engine* engine, const std::string& name, std::vector<std::uniqu
     scripting::on_ui_open(document, std::move(args));
     menu->addPage(name, document->getRoot());
     menu->setPage(name);
+    return document;
 }
 
 void menus::show_process_panel(Engine* engine, std::shared_ptr<Task> task, std::wstring text) {
-    auto menu = engine->getGUI()->getMenu();
-    auto panel = std::dynamic_pointer_cast<gui::Panel>(guiutil::create(
-        "<panel size='400' padding='8' interval='1' color='#00000080/>"
-    ));
-    if (!text.empty()) {
-        panel->add(std::make_shared<gui::Label>(langs::get(text)));
-    }
-
-    auto label = std::make_shared<gui::Label>(L"0%");
-    panel->add(label);
-
+    using namespace dynamic;
+    
     uint initialWork = task->getWorkTotal();
 
-    panel->listenInterval(0.01f, [=]() {
+    auto menu = engine->getGUI()->getMenu();
+    menu->reset();
+    std::vector<std::unique_ptr<dynamic::Value>> args;
+    args.emplace_back(Value::of(util::wstr2str_utf8(langs::get(text))));
+    auto doc = menus::show(engine, "process", std::move(args));
+    std::dynamic_pointer_cast<Container>(doc->getRoot())->listenInterval(0.01f, [=]() {
         task->update();
 
         uint tasksDone = task->getWorkDone();
-        float progress = tasksDone/static_cast<float>(initialWork);
-        label->setText(
-            std::to_wstring(tasksDone)+
-            L"/"+std::to_wstring(initialWork)+L" ("+
-            std::to_wstring(static_cast<int>(progress*100))+L"%)"
-        );
+        scripting::on_ui_progress(doc, tasksDone, initialWork);
     });
-
-    menu->reset();
-    menu->addPage("process", panel);
-    menu->setPage("process", false);
 }
diff --git a/src/frontend/menu.hpp b/src/frontend/menu.hpp
index 3f22b0da..6f2b1000 100644
--- a/src/frontend/menu.hpp
+++ b/src/frontend/menu.hpp
@@ -8,6 +8,8 @@
 class Task;
 class Engine;
 
+class UiDocument;
+
 namespace dynamic {
     class Value;
 }
@@ -15,8 +17,15 @@ namespace dynamic {
 namespace menus {
     /// @brief Create development version label at the top-right screen corner
     void create_version_label(Engine* engine);
+
     void create_menus(Engine* engine);
-    void show(Engine* engine, const std::string& name, std::vector<std::unique_ptr<dynamic::Value>> args);
+
+    UiDocument* show(
+        Engine* engine, 
+        const std::string& name,
+        std::vector<std::unique_ptr<dynamic::Value>> args
+    );
+
     void show_process_panel(Engine* engine, std::shared_ptr<Task> task, std::wstring text=L"");
 }
 
diff --git a/src/frontend/screens/MenuScreen.cpp b/src/frontend/screens/MenuScreen.cpp
index f7b31dd4..a3c88144 100644
--- a/src/frontend/screens/MenuScreen.cpp
+++ b/src/frontend/screens/MenuScreen.cpp
@@ -8,7 +8,10 @@
 #include "../../window/Camera.h"
 #include "../../engine.h"
 
-MenuScreen::MenuScreen(Engine* engine_) : Screen(engine_) {
+MenuScreen::MenuScreen(Engine* engine) : Screen(engine) {
+    engine->getContentPacks().clear();
+    engine->loadContent();
+
     auto menu = engine->getGUI()->getMenu();
     menu->reset();
     menu->setPage("main");
diff --git a/src/graphics/ui/elements/Menu.cpp b/src/graphics/ui/elements/Menu.cpp
index 05fa1aaf..56f35c42 100644
--- a/src/graphics/ui/elements/Menu.cpp
+++ b/src/graphics/ui/elements/Menu.cpp
@@ -49,9 +49,9 @@ void Menu::setPage(std::string name, bool history) {
 void Menu::setPage(Page page, bool history) {
     if (current.panel) {
         Container::remove(current.panel);
-    }
-    if (history) {
-        pageStack.push(current);
+        if (history) {
+            pageStack.push(current);
+        }
     }
     current = page;
     Container::add(current.panel);
diff --git a/src/logic/LevelController.cpp b/src/logic/LevelController.cpp
index 430c0e92..733742ad 100644
--- a/src/logic/LevelController.cpp
+++ b/src/logic/LevelController.cpp
@@ -1,4 +1,5 @@
 #include "LevelController.h"
+#include "../files/WorldFiles.h"
 #include "../debug/Logger.h"
 #include "../world/Level.h"
 #include "../world/World.h"
@@ -46,6 +47,7 @@ void LevelController::update(float delta, bool input, bool pause) {
 }
 
 void LevelController::saveWorld() {
+    level->getWorld()->wfile->createDirectories();
     logger.info() << "writing world";
     scripting::on_world_save();
     level->getWorld()->write(level.get());
diff --git a/src/logic/scripting/scripting.cpp b/src/logic/scripting/scripting.cpp
index 95951ced..c520d93c 100644
--- a/src/logic/scripting/scripting.cpp
+++ b/src/logic/scripting/scripting.cpp
@@ -240,6 +240,15 @@ void scripting::on_ui_open(
     });
 }
 
+void scripting::on_ui_progress(UiDocument* layout, int workDone, int workTotal) {
+    std::string name = layout->getId() + ".progress";
+    emit_event(name, [=] (lua::LuaState* state) {
+        state->pushinteger(workDone);
+        state->pushinteger(workTotal);
+        return 2;
+    });
+}
+
 void scripting::on_ui_close(UiDocument* layout, Inventory* inventory) {
     std::string name = layout->getId() + ".close";
     emit_event(name, [inventory] (lua::LuaState* state) {
@@ -330,6 +339,7 @@ void scripting::load_layout_script(scriptenv senv, std::string prefix, fs::path
     state->loadbuffer(env, src, file.u8string());
     state->callNoThrow(0);
     script.onopen = register_event(env, "on_open", prefix+".open");
+    script.onprogress = register_event(env, "on_progress", prefix+".progress");
     script.onclose = register_event(env, "on_close", prefix+".close");
 }
 
diff --git a/src/logic/scripting/scripting.h b/src/logic/scripting/scripting.h
index ec067210..ad69d534 100644
--- a/src/logic/scripting/scripting.h
+++ b/src/logic/scripting/scripting.h
@@ -79,6 +79,8 @@ namespace scripting {
         std::vector<std::unique_ptr<dynamic::Value>> args
     );
 
+    void on_ui_progress(UiDocument* layout, int workDone, int totalWork);
+
     /// @brief Called on UI view close
     void on_ui_close(UiDocument* layout, Inventory* inventory);