diff --git a/res/layouts/inventory.xml b/res/layouts/inventory.xml
index b5ea903c..afe61bbd 100644
--- a/res/layouts/inventory.xml
+++ b/res/layouts/inventory.xml
@@ -1,3 +1,4 @@
-<inventory color="#00000080">
+<inventory color="#00000080" size="400,100">
     <slots-grid cols="4" count="40"/>
+    <button coord="300,10">Test</button>
 </inventory>
diff --git a/res/scripts/world.lua b/res/scripts/world.lua
index e69de29b..964100e7 100644
--- a/res/scripts/world.lua
+++ b/res/scripts/world.lua
@@ -0,0 +1,3 @@
+-- use for engine development tests
+-- must be empty in release
+-- must not be modified by content-packs
diff --git a/src/assets/AssetsLoader.cpp b/src/assets/AssetsLoader.cpp
index 177f2e9e..35babebc 100644
--- a/src/assets/AssetsLoader.cpp
+++ b/src/assets/AssetsLoader.cpp
@@ -66,6 +66,8 @@ void AssetsLoader::addDefaults(AssetsLoader& loader, bool world) {
         loader.add(ASSET_TEXTURE, TEXTURES_FOLDER"/misc/sun.png", "misc/sun");
 
         for (fs::path& file : loader.getPaths()->listdir(LAYOUTS_FOLDER)) {
+            if (file.extension().u8string() != ".xml")
+                continue;
             std::string packName = file.parent_path().parent_path().filename();
             if (packName == "res") {
                 packName = "core";
diff --git a/src/frontend/UiDocument.cpp b/src/frontend/UiDocument.cpp
index 88702084..3d2f774a 100644
--- a/src/frontend/UiDocument.cpp
+++ b/src/frontend/UiDocument.cpp
@@ -10,8 +10,9 @@
 UiDocument::UiDocument(
     std::string namesp, 
     uidocscript script, 
-    std::shared_ptr<gui::UINode> root
-) : namesp(namesp), script(script), root(root) {
+    std::shared_ptr<gui::UINode> root,
+    int env
+) : namesp(namesp), script(script), root(root), env(env) {
     collect(map, root);
 }
 
@@ -53,7 +54,7 @@ std::unique_ptr<UiDocument> UiDocument::read(std::string namesp, fs::path file)
     uidocscript script {};
     auto scriptFile = fs::path(file.u8string()+".lua");
     if (fs::is_regular_file(scriptFile)) {
-        scripting::load_layout_script(scriptFile, script);
+        scripting::load_layout_script(env->getId(), scriptFile, script);
     }
-    return std::make_unique<UiDocument>(namesp, script, view);
+    return std::make_unique<UiDocument>(namesp, script, view, env.release()->getId());
 }
diff --git a/src/frontend/UiDocument.h b/src/frontend/UiDocument.h
index a987ecf3..45484b01 100644
--- a/src/frontend/UiDocument.h
+++ b/src/frontend/UiDocument.h
@@ -25,8 +25,13 @@ class UiDocument {
     uidocscript script;
     uinodes_map map;
     std::shared_ptr<gui::UINode> root;
+    int env;
 public:
-    UiDocument(std::string namesp, uidocscript script, std::shared_ptr<gui::UINode> root);
+    UiDocument(
+        std::string namesp, 
+        uidocscript script, 
+        std::shared_ptr<gui::UINode> root, 
+        int env);
 
     const uinodes_map& getMap() const;
     const std::string& getNamespace() const;
diff --git a/src/frontend/gui/gui_xml.cpp b/src/frontend/gui/gui_xml.cpp
index 67e65e5f..9df72ed6 100644
--- a/src/frontend/gui/gui_xml.cpp
+++ b/src/frontend/gui/gui_xml.cpp
@@ -117,7 +117,11 @@ static std::shared_ptr<UINode> readButton(UiXmlReader& reader, xml::xmlelement e
     _readPanel(reader, element, *button);
 
     if (element->has("onclick")) {
-        auto callback = scripting::create_runnable("<onclick>", element->attr("onclick").getText(), reader.getEnvironment());
+        auto callback = scripting::create_runnable(
+            reader.getEnvironment().getId(),
+            "<onclick>", 
+            element->attr("onclick").getText()
+        );
         button->listenAction([callback](GUI*) {
             callback();
         });
@@ -137,6 +141,7 @@ static std::shared_ptr<UINode> readTextBox(UiXmlReader& reader, xml::xmlelement
 
     if (element->has("consumer")) {
         auto consumer = scripting::create_wstring_consumer(
+            reader.getEnvironment().getId(),
             element->attr("consumer").getText(),
             reader.getFilename()
         );
diff --git a/src/logic/scripting/LuaState.cpp b/src/logic/scripting/LuaState.cpp
index 5e4b6983..8d3836c0 100644
--- a/src/logic/scripting/LuaState.cpp
+++ b/src/logic/scripting/LuaState.cpp
@@ -25,8 +25,12 @@ lua::LuaState::LuaState() {
 
     createFuncs();
 
-    lua_getglobal(L, "_G");
-    lua_setglobal(L, ":G");
+    lua_pushvalue(L, LUA_GLOBALSINDEX);
+    setglobal(envName(0));
+}
+
+const std::string lua::LuaState::envName(int env) const {
+    return "_ENV"+util::mangleid(env);
 }
 
 lua::LuaState::~LuaState() {
@@ -109,10 +113,13 @@ void lua::LuaState::createFuncs() {
     addfunc("set_block_user_bits", l_set_block_user_bits);
 }
 
-void lua::LuaState::loadbuffer(const std::string& src, const std::string& file) {
+void lua::LuaState::loadbuffer(int env, const std::string& src, const std::string& file) {
     if (luaL_loadbuffer(L, src.c_str(), src.length(), file.c_str())) {
         throw lua::luaerror(lua_tostring(L, -1));
     }
+    if (env && getglobal(envName(env))) {
+        lua_setfenv(L, -2);
+    }
 }
 
 int lua::LuaState::call(int argc) {
@@ -130,14 +137,14 @@ int lua::LuaState::callNoThrow(int argc) {
     return 1;
 }
 
-int lua::LuaState::eval(const std::string& src, const std::string& file) {
+int lua::LuaState::eval(int env, const std::string& src, const std::string& file) {
     auto srcText = "return ("+src+")";
-    loadbuffer(srcText, file);
+    loadbuffer(env, srcText, file);
     return call(0);
 }
 
-int lua::LuaState::execute(const std::string& src, const std::string& file) {
-    loadbuffer(src, file);
+int lua::LuaState::execute(int env, const std::string& src, const std::string& file) {
+    loadbuffer(env, src, file);
     return callNoThrow(0);
 }
 
@@ -186,49 +193,24 @@ const std::string lua::LuaState::storeAnonymous() {
     return funcName;
 }
 
-void lua::LuaState::initEnvironment() {
-    lua_getglobal(L, "_G");
-    lua_setfield(L, -1, ":G");
-}
-
 int lua::LuaState::createEnvironment() {
     int id = nextEnvironment++;
+    // globals table
+    lua_createtable(L, 0, 1);
+    
+    // metatable
+    lua_createtable(L, 0, 1);
 
-    if (currentEnvironment != 0) {
-        setEnvironment(0);
-    }
+    lua_pushvalue(L, LUA_GLOBALSINDEX);
+    lua_setfield(L, -2, "__index");
+    lua_setmetatable(L, -2);
 
-    lua_createtable(L, 0, 0);
-    initEnvironment();
-    setglobal("_N"+util::mangleid(id));
-
-    setEnvironment(id);
+    setglobal(envName(id));
     return id;
 }
 
+
 void lua::LuaState::removeEnvironment(int id) {
-    if (currentEnvironment == id) {
-        setEnvironment(0);
-    }
     lua_pushnil(L);
-    setglobal("_N"+util::mangleid(id));
-}
-
-int lua::LuaState::getEnvironment() const {
-    return currentEnvironment;
-}
-
-void lua::LuaState::setEnvironment(int id) {
-    if (id == 0) {
-        getglobal(":G");
-        lua_setfenv(L, -1);
-    } else {
-        getglobal(":G");
-        lua_getfield(L, -1, ("_N"+util::mangleid(id)).c_str());
-        if (lua_isnil(L, -1)) {
-            lua_pop(L, -1);
-            throw luaerror("environment "+std::to_string(id)+" was not found");
-        }
-        lua_setfenv(L, -1);
-    }
+    setglobal(envName(id));
 }
diff --git a/src/logic/scripting/LuaState.h b/src/logic/scripting/LuaState.h
index d2f64da7..71a231cd 100644
--- a/src/logic/scripting/LuaState.h
+++ b/src/logic/scripting/LuaState.h
@@ -17,7 +17,6 @@ namespace lua {
     class LuaState {
         lua_State* L;
         int nextEnvironment = 1;
-        int currentEnvironment = 0;
 
         void logError(const std::string& text);
         void initEnvironment();
@@ -25,7 +24,8 @@ namespace lua {
         LuaState();
         ~LuaState();
 
-        void loadbuffer(const std::string& src, const std::string& file);
+        const std::string envName(int env) const;
+        void loadbuffer(int env, const std::string& src, const std::string& file);
         int gettop() const;
         int pushivec3(luaint x, luaint y, luaint z);
         int pushinteger(luaint x);
@@ -35,8 +35,8 @@ namespace lua {
         luaint tointeger(int index);
         int call(int argc);
         int callNoThrow(int argc);
-        int execute(const std::string& src, const std::string& file="<string>");
-        int eval(const std::string& src, const std::string& file="<eval>");
+        int execute(int env, const std::string& src, const std::string& file="<string>");
+        int eval(int env, const std::string& src, const std::string& file="<eval>");
         void openlib(const std::string& name, const luaL_Reg* libfuncs, int nup);
         void addfunc(const std::string& name, lua_CFunction func);
         bool getglobal(const std::string& name);
@@ -47,9 +47,6 @@ namespace lua {
         void createFuncs();
         int createEnvironment();
         void removeEnvironment(int id);
-        int getEnvironment() const;
-        void setEnvironment(int id);
-
         const std::string storeAnonymous();
     };
 }
diff --git a/src/logic/scripting/scripting.cpp b/src/logic/scripting/scripting.cpp
index 985fd173..de2056e5 100644
--- a/src/logic/scripting/scripting.cpp
+++ b/src/logic/scripting/scripting.cpp
@@ -47,7 +47,7 @@ void load_script(fs::path name) {
     fs::path file = paths->getResources()/fs::path("scripts")/name;
 
     std::string src = files::read_string(file);
-    state->execute(src, file.u8string());
+    state->execute(0, src, file.u8string());
 }
 
 void scripting::initialize(Engine* engine) {
@@ -58,35 +58,23 @@ void scripting::initialize(Engine* engine) {
     load_script(fs::path("stdlib.lua"));
 }
 
-// todo: luaL state check
 runnable scripting::create_runnable(
+    int env,
     const std::string& file,
     const std::string& src
 ) {
     return [=](){
-        state->execute(src, file);
-    };
-}
-
-runnable scripting::create_runnable(
-    const std::string& file,
-    const std::string& src,
-    const Environment& env
-) {
-    return [=](){
-        int previous = state->getEnvironment();
-        state->setEnvironment(env.getId());
-        state->execute(src, file);
-        state->setEnvironment(previous);
+        state->execute(env, src, file);
     };
 }
 
 wstringconsumer scripting::create_wstring_consumer(
+    int env,
     const std::string& src,
     const std::string& file
 ) {
     try {
-        if (state->eval(src, file) == 0)
+        if (state->eval(env, src, file) == 0)
             return [](const std::wstring& _) {};
     } catch (const lua::luaerror& err) {
         std::cerr << err.what() << std::endl;
@@ -220,7 +208,7 @@ bool scripting::on_item_break_block(Player* player, const ItemDef* item, int x,
 void scripting::load_block_script(std::string prefix, fs::path file, block_funcs_set& funcsset) {
     std::string src = files::read_string(file);
     std::cout << "loading script " << file.u8string() << std::endl;
-    state->execute(src, file.u8string());
+    state->execute(0, src, file.u8string());
 
     funcsset.init=state->rename("init", prefix+".init");
     funcsset.update=state->rename("on_update", prefix+".update");
@@ -234,7 +222,7 @@ void scripting::load_block_script(std::string prefix, fs::path file, block_funcs
 void scripting::load_item_script(std::string prefix, fs::path file, item_funcs_set& funcsset) {
     std::string src = files::read_string(file);
     std::cout << "loading script " << file.u8string() << std::endl;
-    state->execute(src, file.u8string());
+    state->execute(0, src, file.u8string());
     funcsset.init=state->rename("init", prefix+".init");
     funcsset.on_use_on_block=state->rename("on_use_on_block", prefix+".useon");
     funcsset.on_block_break_by=state->rename("on_block_break_by", prefix+".blockbreakby");
@@ -244,7 +232,7 @@ void scripting::load_world_script(std::string prefix, fs::path file) {
     std::string src = files::read_string(file);
     std::cout << "loading script " << file.u8string() << std::endl;
 
-    state->loadbuffer(src, file.u8string());
+    state->loadbuffer(0, src, file.u8string());
     state->callNoThrow(0);
 
     state->rename("init", prefix+".init");
@@ -253,12 +241,12 @@ void scripting::load_world_script(std::string prefix, fs::path file) {
     state->rename("on_world_quit", prefix+".worldquit");
 }
 
-void scripting::load_layout_script(fs::path file, uidocscript& script) {
+void scripting::load_layout_script(int env, fs::path file, uidocscript& script) {
     std::string src = files::read_string(file);
     std::cout << "loading script " << file.u8string() << std::endl;
 
-    script.environment = state->createEnvironment();
-    state->loadbuffer(src, file.u8string());
+    script.environment = env;
+    state->loadbuffer(env, src, file.u8string());
     state->callNoThrow(0);
     script.onopen = state->hasglobal("on_open");
     script.onclose = state->hasglobal("on_close");
diff --git a/src/logic/scripting/scripting.h b/src/logic/scripting/scripting.h
index b8fe6f55..64bbc452 100644
--- a/src/logic/scripting/scripting.h
+++ b/src/logic/scripting/scripting.h
@@ -38,17 +38,13 @@ namespace scripting {
     void initialize(Engine* engine);
 
     runnable create_runnable(
+        int env,
         const std::string& filename,
         const std::string& source
     );
-
-    runnable create_runnable(
-        const std::string& filename,
-        const std::string& source,
-        const Environment& env
-    );
     
     wstringconsumer create_wstring_consumer(
+        int env,
         const std::string& src,
         const std::string& file="<string>"
     );
@@ -69,6 +65,6 @@ namespace scripting {
     void load_block_script(std::string prefix, fs::path file, block_funcs_set& funcsset);
     void load_item_script(std::string prefix, fs::path file, item_funcs_set& funcsset);
     void load_world_script(std::string prefix, fs::path file);
-    void load_layout_script(fs::path file, uidocscript& script);
+    void load_layout_script(int env, fs::path file, uidocscript& script);
     void close();
 }