diff --git a/doc/en/scripting/builtins/libapp.md b/doc/en/scripting/builtins/libapp.md
index 2b5a74cd..0ec75568 100644
--- a/doc/en/scripting/builtins/libapp.md
+++ b/doc/en/scripting/builtins/libapp.md
@@ -159,6 +159,11 @@ app.get_setting_info(name: str) -> {
 
 Returns a table with information about a setting. Throws an exception if the setting does not exist.
 
+```lua
+app.focus()
+```
+
+Brings the window to front and sets input focus.
 
 ```lua
 app.create_memory_device(
diff --git a/doc/en/scripting/builtins/libinput.md b/doc/en/scripting/builtins/libinput.md
index 2c577389..9856abc0 100644
--- a/doc/en/scripting/builtins/libinput.md
+++ b/doc/en/scripting/builtins/libinput.md
@@ -13,7 +13,16 @@ input.mousecode(mousename: str) --> int
 Returns mouse button code or -1 if unknown
 
 ```lua
-input.add_callback(bindname: str, callback: function)
+input.add_callback(
+    -- Binding name
+    bindname: str,
+    -- Handler
+    callback: function
+    -- UI element that owns the handler (responsible for the handler's lifetime)
+    [optional] owner: Element,
+    -- Ignore input capture by UI elements
+    [optional] istoplevel: bool
+)
 ```
 
 Add binding activation callback. Example:
diff --git a/doc/en/scripting/builtins/libnetwork.md b/doc/en/scripting/builtins/libnetwork.md
index 515488f7..3ceac9c8 100644
--- a/doc/en/scripting/builtins/libnetwork.md
+++ b/doc/en/scripting/builtins/libnetwork.md
@@ -82,6 +82,16 @@ socket:recv(
 -- Returns nil on error (socket is closed or does not exist).
 -- If there is no data yet, returns an empty byte array.
 
+-- Asynchronous version for use in coroutines.
+-- Waits for the entire specified number of bytes to be received.
+-- If socket closes, function works like socket:recv
+socket:recv_async(
+    -- Size of the byte array to read
+    length: int,
+    -- Use table instead of Bytearray
+    [optional] usetable: bool=false
+) -> nil|table|Bytearray
+
 -- Closes the connection
 socket:close()
 
@@ -137,5 +147,5 @@ network.get_total_download() --> int
 
 ```lua
 -- Looks for a free port to use.
-network.find_free_port() --> int
+network.find_free_port() --> int or nil
 ```
diff --git a/doc/en/xml-ui-layouts.md b/doc/en/xml-ui-layouts.md
index 1127d79f..5a4d7be4 100644
--- a/doc/en/xml-ui-layouts.md
+++ b/doc/en/xml-ui-layouts.md
@@ -136,6 +136,7 @@ The key code for comparison can be obtained via `input.keycode("key_name")`
 - `text-wrap` - allows automatic text wrapping (works only with multiline: "true")
 - `editable` - determines whether the text can be edited.
 - `line-numbers` - enables line numbers display.
+- `keep-line-selection` - keep showing selected line after defocus.
 - `error-color` - color when entering incorrect data (the text does not pass the validator check). Type: RGBA color.
 - `text-color` - text color. Type: RGBA color.
 - `validator` - lua function that checks text for correctness. Takes a string as input, returns true if the text is correct.
diff --git a/doc/ru/scripting/builtins/libapp.md b/doc/ru/scripting/builtins/libapp.md
index 128232bf..d8a1e81c 100644
--- a/doc/ru/scripting/builtins/libapp.md
+++ b/doc/ru/scripting/builtins/libapp.md
@@ -161,6 +161,11 @@ app.get_setting_info(name: str) -> {
 Возвращает таблицу с информацией о настройке. Бросает исключение, если настройки не существует.
 
 ```lua
+app.focus()
+```
+
+Переводит окно на передний план и устанавливает фокус ввода.
+
 app.create_memory_device(
     -- имя точки входа
     name: str
diff --git a/doc/ru/scripting/builtins/libinput.md b/doc/ru/scripting/builtins/libinput.md
index 96bc3105..6aadbdc1 100644
--- a/doc/ru/scripting/builtins/libinput.md
+++ b/doc/ru/scripting/builtins/libinput.md
@@ -13,7 +13,16 @@ input.mousecode(mousename: str) --> int
 Возвращает код кнопки мыши по имени, либо -1
 
 ```lua
-input.add_callback(bindname: str, callback: function)
+input.add_callback(
+    -- Имя привязки
+    bindname: str,
+    -- Обработчик
+    callback: function
+    -- UI элемент-владелец обработчика (отвечает за срок жизни)
+    [опционально] owner: Element,
+    -- Игнорировать захват ввода UI элементами
+    [опционально] istoplevel: bool    
+)
 ```
 
 Назначает функцию, которая будет вызываться при активации привязки. Пример:
diff --git a/doc/ru/scripting/builtins/libnetwork.md b/doc/ru/scripting/builtins/libnetwork.md
index 269b1615..8c574f36 100644
--- a/doc/ru/scripting/builtins/libnetwork.md
+++ b/doc/ru/scripting/builtins/libnetwork.md
@@ -82,6 +82,16 @@ socket:recv(
 -- В случае ошибки возвращает nil (сокет закрыт или несуществует).
 -- Если данных пока нет, возвращает пустой массив байт.
 
+-- Асинхронный вариант для использования в корутинах.
+-- Ожидает получение всего указанного числа байт.
+-- При закрытии сокета работает как socket:recv
+socket:recv_async(
+    -- Размер читаемого массива байт
+    length: int, 
+    -- Использовать таблицу вместо Bytearray
+    [опционально] usetable: bool=false
+) -> nil|table|Bytearray
+
 -- Закрывает соединение
 socket:close()
 
@@ -202,5 +212,5 @@ network.get_total_download() --> int
 
 ```lua
 -- Ищет свободный для использования порт.
-network.find_free_port() --> int
+network.find_free_port() --> int или nil
 ```
diff --git a/doc/ru/xml-ui-layouts.md b/doc/ru/xml-ui-layouts.md
index a2f068ca..b6efa7b2 100644
--- a/doc/ru/xml-ui-layouts.md
+++ b/doc/ru/xml-ui-layouts.md
@@ -137,6 +137,7 @@
 - `text-wrap` - разрешает автоматический перенос текста (работает только при multiline: "true")
 - `editable`- определяет возможность редактирования текста.
 - `line-numbers` - включает отображение номеров строк.
+- `keep-line-selection` - продолжать отображать выбранную строку при потере фокуса.
 - `error-color` - цвет при вводе некорректных данных (текст не проходит проверку валидатора). Тип: RGBA цвет.
 - `text-color` - цвет текста. Тип: RGBA цвет.
 - `validator` - lua функция, проверяющая текст на корректность. Принимает на вход строку, возвращает true если текст корректен.
diff --git a/doc/specs/debugging_protocol.md b/doc/specs/debugging_protocol.md
new file mode 100644
index 00000000..ba4cf96a
--- /dev/null
+++ b/doc/specs/debugging_protocol.md
@@ -0,0 +1,153 @@
+# VC-DBG protocol v1
+
+## Notes
+
+- '?' in name means that the attribute is optional.
+
+## Connecting
+
+### Step 1
+
+Connection initiating with binary header exchange:
+
+```
+'v' 'c' '-' 'd' 'b' 'g' NUL XX
+76  63  2D  64  62  67  00  XX
+```
+
+XX - protocol version number
+
+Client sends header to the server. Then server responds.
+Server closes connection after sending header if it mismatches.
+
+### Step 2
+
+Client sends 'connect' command.
+
+## Messages
+
+Message is:
+- 32 bit little-endian unsigned integer - number of encoded message bytes.
+- message itself (UTF-8 encoded json).
+
+## Client-to-server
+
+### Establishing connection
+
+```json
+{
+    "type": "connect",
+    "?disconnect-action": "resume|detach|terminate"
+}
+```
+
+Configuring connection. Disconnect-action is action that debugged instance must perform on debugging client connection closed/refused.
+
+- `resume` - Resume from pause mode and start listening for client.
+- `detach` - Resume from pause mode and stop server.
+- `terminate` - Stop the debugged application.
+
+
+### Specific action signals.
+
+```json
+{
+    "type": "pause|resume|terminate|detach"
+}
+```
+
+### Breakpoints management
+
+```json
+{
+    "type": "set-breakpoint|remove-breakpoint",
+    "source": "entry_point:path",
+    "line": 1
+}
+```
+
+### Local value details request
+
+```json
+{
+    "type": "get-value",
+    "frame": 0,
+    "local": 1,
+    "path": ["path", "to", 1, "value"]
+}
+```
+
+- `frame` - Call stack frame index (indexing from most recent call)
+- `local` - Local variable index (based on `paused` event stack trace)
+- `path` - Requsted value path segments. Example: `['a', 'b', 5]` is `local_variable.a.b[5]`
+
+Responds with:
+
+```json
+{
+    "type": "value",
+    "frame": 0,
+    "local": 1,
+    "path": ["path", "to", 1, "value"],
+    "value": "value itself"
+}
+```
+
+Example: actual value is table: 
+```lua
+{a=5, b="test", 2={}}
+```
+
+Then `value` is:
+```json
+{
+    "a": {
+        "type": "number",
+        "short": "5"
+    },
+    "b": {
+        "type": "string",
+        "short": "test"
+    },
+    "1": {
+        "type": "table",
+        "short": "{...}"
+    }
+}
+```
+
+## Server-to-client
+
+### Response signals
+
+```json
+{
+    "type": "success|resumed"
+}
+```
+
+### Pause event
+
+```json
+{
+    "type": "paused",
+    "?reason": "breakpoint|exception|step",
+    "?message": "...",
+    "?stack": [
+        {
+            "?function": "function name",
+            "source": "source name",
+            "what": "what",
+            "line": 1,
+            "locals": [
+                "name": {
+                    "type": "local type",
+                    "index": 1,
+                    "short": "short value",
+                    "size": 0
+                }
+            ]
+        }
+    ]
+}
+```
diff --git a/res/devtools/syntax/lua.toml b/res/devtools/syntax/lua.toml
index cbccce75..d2469d2f 100644
--- a/res/devtools/syntax/lua.toml
+++ b/res/devtools/syntax/lua.toml
@@ -8,5 +8,5 @@ multiline-string-end = "]]"
 keywords = [
     "and", "break", "do", "else", "elseif", "end", "false", "for", "function", 
     "if", "in", "local", "nil", "not", "or", "repeat", "return", "then", "true",
-    "until", "while"
+    "until", "while", "self", "error"
 ]
diff --git a/res/modules/internal/debugging.lua b/res/modules/internal/debugging.lua
index cef40202..1b56ee4b 100644
--- a/res/modules/internal/debugging.lua
+++ b/res/modules/internal/debugging.lua
@@ -60,7 +60,9 @@ if is_debugging then
         current_func = _debug_getinfo(2).func
         current_func_stack_size = calc_stack_size()
         __pause("breakpoint")
-        debug.pull_events()
+        while debug.pull_events() do
+            __pause()
+        end
     end, "lr")
 end
 
@@ -92,6 +94,7 @@ function debug.pull_events()
     if not events then
         return
     end
+    local keepPaused = false
     for i, event in ipairs(events) do
         if event[1] == DBG_EVENT_SET_BREAKPOINT then
             debug.set_breakpoint(event[2], event[3])
@@ -116,9 +119,10 @@ function debug.pull_events()
                 value = value[key]
             end
             __sendvalue(value, event[2], event[3], event[4])
-            __pause()
+            keepPaused = true
         end
     end
+    return keepPaused
 end
 
 function debug.set_breakpoint(source, line)
diff --git a/res/modules/schedule.lua b/res/modules/schedule.lua
index 457cbf90..3c75ead8 100644
--- a/res/modules/schedule.lua
+++ b/res/modules/schedule.lua
@@ -3,7 +3,7 @@ local Schedule = {
         set_interval = function(self, ms, callback, repetions)
             local id = self._next_interval
             self._intervals[id] = {
-                last_called = 0.0,
+                last_called = self._timer,
                 delay = ms / 1000.0,
                 callback = callback,
                 repetions = repetions,
diff --git a/res/scripts/classes.lua b/res/scripts/classes.lua
index 9076808c..f55a503b 100644
--- a/res/scripts/classes.lua
+++ b/res/scripts/classes.lua
@@ -39,6 +39,16 @@ end
 local Socket = {__index={
     send=function(self, ...) return network.__send(self.id, ...) end,
     recv=function(self, ...) return network.__recv(self.id, ...) end,
+    recv_async=function(self, length, usetable)
+        while self:is_alive() do
+            local available = self:available()
+            if available >= length then
+                return self:recv(length, usetable)
+            end
+            coroutine.yield()
+        end
+        return self:recv(length, usetable)
+    end,
     close=function(self) return network.__close(self.id) end,
     available=function(self) return network.__available(self.id) or 0 end,
     is_alive=function(self) return network.__is_alive(self.id) end,
diff --git a/res/scripts/stdlib.lua b/res/scripts/stdlib.lua
index 945f63a2..f8cb1c07 100644
--- a/res/scripts/stdlib.lua
+++ b/res/scripts/stdlib.lua
@@ -47,6 +47,7 @@ local function complete_app_lib(app)
     end
     app.reset_content = core.reset_content
     app.is_content_loaded = core.is_content_loaded
+    app.set_title = core.set_title
     
     function app.config_packs(packs_list)
         -- Check if packs are valid and add dependencies to the configuration
diff --git a/src/devtools/DebuggingServer.cpp b/src/devtools/DebuggingServer.cpp
index 09a2b368..b1aba638 100644
--- a/src/devtools/DebuggingServer.cpp
+++ b/src/devtools/DebuggingServer.cpp
@@ -197,6 +197,7 @@ bool DebuggingServer::performCommand(
         connectionEstablished = true;
         logger.info() << "client connection established";
         connection->sendResponse("success");
+        return true;
     }
     if (!connectionEstablished) {
         return false;
diff --git a/src/engine/Engine.cpp b/src/engine/Engine.cpp
index 6598562f..67ff6797 100644
--- a/src/engine/Engine.cpp
+++ b/src/engine/Engine.cpp
@@ -70,6 +70,7 @@ void Engine::onContentLoad() {
     for (auto& pack : content->getAllContentPacks()) {
         auto configFolder = pack.folder / "config";
         auto bindsFile = configFolder / "bindings.toml";
+        logger.info() << "loading bindings: " << bindsFile.string();
         if (io::is_regular_file(bindsFile)) {
             input->getBindings().read(
                 toml::parse(
diff --git a/src/engine/EnginePaths.cpp b/src/engine/EnginePaths.cpp
index 82aea253..6c05614e 100644
--- a/src/engine/EnginePaths.cpp
+++ b/src/engine/EnginePaths.cpp
@@ -72,6 +72,14 @@ EnginePaths::EnginePaths(CoreParameters& params)
     io::create_subdevice("config", "user", "config");
 }
 
+std::filesystem::path EnginePaths::getResourcesFolder() const {
+    return resourcesFolder;
+}
+
+std::filesystem::path EnginePaths::getUserFilesFolder() const {
+    return userFilesFolder;
+}
+
 io::path EnginePaths::getNewScreenshotFile(const std::string& ext) const {
     auto folder = SCREENSHOTS_FOLDER;
     if (!io::is_directory(folder)) {
diff --git a/src/engine/EnginePaths.hpp b/src/engine/EnginePaths.hpp
index 8e5f71a2..876394b4 100644
--- a/src/engine/EnginePaths.hpp
+++ b/src/engine/EnginePaths.hpp
@@ -48,6 +48,9 @@ public:
 
     EnginePaths(CoreParameters& params);
 
+    std::filesystem::path getResourcesFolder() const;
+    std::filesystem::path getUserFilesFolder() const;
+
     io::path getWorldFolderByName(const std::string& name);
     io::path getWorldsFolder() const;
 
diff --git a/src/engine/WindowControl.cpp b/src/engine/WindowControl.cpp
index 5ae96965..a93c1599 100644
--- a/src/engine/WindowControl.cpp
+++ b/src/engine/WindowControl.cpp
@@ -33,11 +33,12 @@ WindowControl::Result WindowControl::initialize() {
     auto& settings = engine.getSettings();
 
     std::string title = project.title;
-    if (title.empty()) {
-        title = "VoxelCore v" +
-                        std::to_string(ENGINE_VERSION_MAJOR) + "." +
-                        std::to_string(ENGINE_VERSION_MINOR);
+    if (!title.empty()) {
+        title += " - ";
     }
+    title += "VoxelCore v" +
+                    std::to_string(ENGINE_VERSION_MAJOR) + "." +
+                    std::to_string(ENGINE_VERSION_MINOR);
     if (ENGINE_DEBUG_BUILD) {
         title += " [debug]";
     }
diff --git a/src/graphics/ui/elements/Container.cpp b/src/graphics/ui/elements/Container.cpp
index 69217637..aa9b5977 100644
--- a/src/graphics/ui/elements/Container.cpp
+++ b/src/graphics/ui/elements/Container.cpp
@@ -93,10 +93,9 @@ void Container::act(float delta) {
             }
         }
     }
-    GUI& gui = this->gui;
     intervalEvents.erase(std::remove_if(
         intervalEvents.begin(), intervalEvents.end(),
-        [&gui](const IntervalEvent& event) {
+        [](const IntervalEvent& event) {
             return event.repeat == 0;
         }
     ), intervalEvents.end());
@@ -177,6 +176,7 @@ void Container::add(const std::shared_ptr<UINode>& node) {
         parent->setMustRefresh();
         parent = parent->getParent();
     }
+    gui.getWindow().setShouldRefresh();
 }
 
 void Container::add(const std::shared_ptr<UINode>& node, glm::vec2 pos) {
diff --git a/src/graphics/ui/elements/Container.hpp b/src/graphics/ui/elements/Container.hpp
index dd7dfd34..0506bf38 100644
--- a/src/graphics/ui/elements/Container.hpp
+++ b/src/graphics/ui/elements/Container.hpp
@@ -37,7 +37,9 @@ namespace gui {
         virtual void scrolled(int value) override;
         virtual void setScrollable(bool flag);
         void listenInterval(float interval, OnTimeOut callback, int repeat=-1);
-        virtual glm::vec2 getContentOffset() override {return glm::vec2(0.0f, scroll);};
+        virtual glm::vec2 getContentOffset() const override {
+            return glm::vec2(0.0f, scroll);
+        };
         virtual void setSize(const glm::vec2& size) override;
         virtual int getScrollStep() const;
         virtual void setScrollStep(int step);
diff --git a/src/graphics/ui/elements/InlineFrame.cpp b/src/graphics/ui/elements/InlineFrame.cpp
index 35c7b639..50fc7976 100644
--- a/src/graphics/ui/elements/InlineFrame.cpp
+++ b/src/graphics/ui/elements/InlineFrame.cpp
@@ -36,12 +36,11 @@ void InlineFrame::setDocument(const std::shared_ptr<UiDocument>& document) {
 }
 
 void InlineFrame::act(float delta) {
-    Container::act(delta);
-    if (document || src.empty()) {
-        return;
+    if (document == nullptr && !src.empty()) {
+        const auto& assets = *gui.getEngine().getAssets();
+        setDocument(assets.getShared<UiDocument>(src));
     }
-    const auto& assets = *gui.getEngine().getAssets();
-    setDocument(assets.getShared<UiDocument>(src));
+    Container::act(delta);
 }
 
 void InlineFrame::setSize(const glm::vec2& size) {
diff --git a/src/graphics/ui/elements/TextBox.cpp b/src/graphics/ui/elements/TextBox.cpp
index 5e7ab370..83c15544 100644
--- a/src/graphics/ui/elements/TextBox.cpp
+++ b/src/graphics/ui/elements/TextBox.cpp
@@ -231,7 +231,7 @@ TextBox::~TextBox() = default;
 void TextBox::draw(const DrawContext& pctx, const Assets& assets) {
     Container::draw(pctx, assets);
 
-    if (!isFocused()) {
+    if (!isFocused() && !keepLineSelection) {
         return;
     }
     const auto& labelText = getText();
@@ -252,7 +252,7 @@ void TextBox::draw(const DrawContext& pctx, const Assets& assets) {
 
     float time = gui.getWindow().time();
 
-    if (editable && static_cast<int>((time - caretLastMove) * 2) % 2 == 0) {
+    if (isFocused() && editable && static_cast<int>((time - caretLastMove) * 2) % 2 == 0) {
         uint line = label->getLineByTextIndex(caret);
         uint lcaret = caret - label->getTextLineOffset(line);
         int width = rawTextCache.metrics.calcWidth(input, 0, lcaret);
@@ -308,42 +308,44 @@ void TextBox::draw(const DrawContext& pctx, const Assets& assets) {
         }
     }
 
-    if (isFocused() && multiline) {
-        auto selectionCtx = subctx.sub(batch);
-        selectionCtx.setBlendMode(BlendMode::addition);
-
-        batch->setColor(glm::vec4(1, 1, 1, 0.1f));
-
-        uint line = label->getLineByTextIndex(caret);
-        while (label->isFakeLine(line)) {
-            line--;
-        }
-        do {
-            int lineY = label->getLineYOffset(line);
-
-            batch->setColor(glm::vec4(1, 1, 1, 0.05f));
-            if (showLineNumbers) {
-                batch->rect(
-                    lcoord.x - 8,
-                    lcoord.y + lineY,
-                    label->getSize().x,
-                    lineHeight
-                );
-                batch->setColor(glm::vec4(1, 1, 1, 0.10f));
-                batch->rect(
-                    lcoord.x - LINE_NUMBERS_PANE_WIDTH,
-                    lcoord.y + lineY,
-                    LINE_NUMBERS_PANE_WIDTH - 8,
-                    lineHeight
-                );
-            } else {
-                batch->rect(
-                    lcoord.x, lcoord.y + lineY, label->getSize().x, lineHeight
-                );
-            }
-            line++;
-        } while (line < label->getLinesNumber() && label->isFakeLine(line));
+    if (!multiline) {
+        return;
     }
+
+    auto selectionCtx = subctx.sub(batch);
+    selectionCtx.setBlendMode(BlendMode::addition);
+
+    batch->setColor(glm::vec4(1, 1, 1, 0.1f));
+
+    uint line = label->getLineByTextIndex(caret);
+    while (label->isFakeLine(line)) {
+        line--;
+    }
+    do {
+        int lineY = label->getLineYOffset(line);
+
+        batch->setColor(glm::vec4(1, 1, 1, 0.05f));
+        if (showLineNumbers) {
+            batch->rect(
+                lcoord.x - 8,
+                lcoord.y + lineY,
+                label->getSize().x,
+                lineHeight
+            );
+            batch->setColor(glm::vec4(1, 1, 1, 0.10f));
+            batch->rect(
+                lcoord.x - LINE_NUMBERS_PANE_WIDTH,
+                lcoord.y + lineY,
+                LINE_NUMBERS_PANE_WIDTH - 8,
+                lineHeight
+            );
+        } else {
+            batch->rect(
+                lcoord.x, lcoord.y + lineY, label->getSize().x, lineHeight
+            );
+        }
+        line++;
+    } while (line < label->getLinesNumber() && label->isFakeLine(line));
 }
 
 void TextBox::drawBackground(const DrawContext& pctx, const Assets& assets) {
@@ -605,6 +607,14 @@ size_t TextBox::getSelectionEnd() const {
     return selectionEnd;
 }
 
+void TextBox::setKeepLineSelection(bool flag) {
+    keepLineSelection = flag;
+}
+
+bool TextBox::isKeepLineSelection() const {
+    return keepLineSelection;
+}
+
 void TextBox::setOnEditStart(runnable oneditstart) {
     onEditStart = oneditstart;
 }
@@ -671,6 +681,11 @@ int TextBox::calcIndexAt(int x, int y) const {
     );
 }
 
+int TextBox::getLineYOffset(int line) const {
+    if (rawTextCache.fontId == 0) return 0;
+    return label->getLineYOffset(line);
+}
+
 static inline std::wstring get_alphabet(wchar_t c) {
     std::wstring alphabet {c};
     if ((c >= 'A' && c <= 'Z') || (c >= 'a' && c <= 'z') || c == '_') {
diff --git a/src/graphics/ui/elements/TextBox.hpp b/src/graphics/ui/elements/TextBox.hpp
index d5b640ac..2f9080a5 100644
--- a/src/graphics/ui/elements/TextBox.hpp
+++ b/src/graphics/ui/elements/TextBox.hpp
@@ -62,6 +62,7 @@ namespace gui {
         bool editable = true;
         bool autoresize = false;
         bool showLineNumbers = false;
+        bool keepLineSelection = false;
         std::string markup;
         std::string syntax;
 
@@ -74,7 +75,6 @@ namespace gui {
 
         size_t normalizeIndex(int index);
 
-        int calcIndexAt(int x, int y) const;
         void setTextOffset(uint x);
         bool eraseSelected();
         void resetSelection();
@@ -186,6 +186,9 @@ namespace gui {
         /// @return line position in text
         virtual size_t getLinePos(uint line) const;
 
+        int calcIndexAt(int x, int y) const;
+        int getLineYOffset(int line) const;
+
         /// @brief Check text with validator set with setTextValidator
         /// @return true if text is valid
         virtual bool validate();
@@ -220,6 +223,9 @@ namespace gui {
         size_t getSelectionStart() const;
         size_t getSelectionEnd() const;
 
+        void setKeepLineSelection(bool flag);
+        bool isKeepLineSelection() const;
+
         /// @brief Set runnable called on textbox focus
         virtual void setOnEditStart(runnable oneditstart);
 
diff --git a/src/graphics/ui/elements/UINode.cpp b/src/graphics/ui/elements/UINode.cpp
index 047c19ad..91973150 100644
--- a/src/graphics/ui/elements/UINode.cpp
+++ b/src/graphics/ui/elements/UINode.cpp
@@ -68,6 +68,10 @@ void UINode::listenClick(OnAction action) {
     actions.listen(UIAction::CLICK, std::move(action));
 }
 
+void UINode::listenRightClick(OnAction action) {
+    actions.listen(UIAction::RIGHT_CLICK, std::move(action));
+}
+
 void UINode::listenDoubleClick(OnAction action) {
     actions.listen(UIAction::DOUBLE_CLICK, std::move(action));
 }
@@ -84,6 +88,12 @@ void UINode::click(int, int) {
     pressed = true;
 }
 
+void UINode::clicked(Mousecode button) {
+    if (button == Mousecode::BUTTON_2) {
+        actions.notify(UIAction::RIGHT_CLICK, gui);
+    }
+}
+
 void UINode::doubleClick(int x, int y) {
     pressed = true;
     if (isInside(glm::vec2(x, y))) {
diff --git a/src/graphics/ui/elements/UINode.hpp b/src/graphics/ui/elements/UINode.hpp
index 695624bb..db9b97dc 100644
--- a/src/graphics/ui/elements/UINode.hpp
+++ b/src/graphics/ui/elements/UINode.hpp
@@ -75,7 +75,7 @@ namespace gui {
     };
 
     enum class UIAction {
-        CLICK, DOUBLE_CLICK, FOCUS, DEFOCUS
+        CLICK, DOUBLE_CLICK, FOCUS, DEFOCUS, RIGHT_CLICK
     };
 
     using ActionsSet = TaggedCallbacksSet<UIAction, GUI&>;
@@ -214,6 +214,7 @@ namespace gui {
         int getZIndex() const;
 
         virtual void listenClick(OnAction action);
+        virtual void listenRightClick(OnAction action);
         virtual void listenDoubleClick(OnAction action);
         virtual void listenFocus(OnAction action);
         virtual void listenDefocus(OnAction action);
@@ -221,7 +222,7 @@ namespace gui {
         virtual void onFocus();
         virtual void doubleClick(int x, int y);
         virtual void click(int x, int y);
-        virtual void clicked(Mousecode button) {}
+        virtual void clicked(Mousecode button);
         virtual void mouseMove(int x, int y) {};
         virtual void mouseRelease(int x, int y);
         virtual void scrolled(int value);
@@ -266,7 +267,7 @@ namespace gui {
         virtual glm::vec4 calcColor() const;
 
         /// @brief Get inner content offset. Used for scroll
-        virtual glm::vec2 getContentOffset() {return glm::vec2(0.0f);};
+        virtual glm::vec2 getContentOffset() const {return glm::vec2(0.0f);};
         /// @brief Calculate screen position of the element
         virtual glm::vec2 calcPos() const;
         virtual void setPos(const glm::vec2& pos);
diff --git a/src/graphics/ui/gui_xml.cpp b/src/graphics/ui/gui_xml.cpp
index 52febdbc..3e8bcf5d 100644
--- a/src/graphics/ui/gui_xml.cpp
+++ b/src/graphics/ui/gui_xml.cpp
@@ -181,6 +181,10 @@ static void read_uinode(
         node.listenClick(onclick);
     }
 
+    if (auto onclick = create_action(reader, element, "onrightclick")) {
+        node.listenRightClick(onclick);
+    }
+
     if (auto onfocus = create_action(reader, element, "onfocus")) {
         node.listenFocus(onfocus);
     }
@@ -569,6 +573,11 @@ static std::shared_ptr<UINode> read_text_box(
     if (element.has("line-numbers")) {
         textbox->setShowLineNumbers(element.attr("line-numbers").asBool());
     }
+    if (element.has("keep-line-selection")) {
+        textbox->setKeepLineSelection(
+            element.attr("keep-line-selection").asBool()
+        );
+    }
     if (element.has("markup")) {
         textbox->setMarkup(element.attr("markup").getText());
     }
diff --git a/src/logic/scripting/lua/libs/libapp.cpp b/src/logic/scripting/lua/libs/libapp.cpp
index 7837c0a4..724bac65 100644
--- a/src/logic/scripting/lua/libs/libapp.cpp
+++ b/src/logic/scripting/lua/libs/libapp.cpp
@@ -2,12 +2,40 @@
 
 #include "io/io.hpp"
 #include "io/devices/MemoryDevice.hpp"
-#include "engine/Engine.hpp"
-#include "content/ContentControl.hpp"
 #include "logic/scripting/scripting.hpp"
+#include "content/ContentControl.hpp"
+#include "engine/Engine.hpp"
+#include "engine/EnginePaths.hpp"
+#include "network/Network.hpp"
+#include "util/platform.hpp"
+#include "window/Window.hpp"
 
 using namespace scripting;
 
+static int l_start_debug_instance(lua::State* L) {
+    int port = lua::tointeger(L, 1);
+    if (port == 0) {
+        port = engine->getNetwork().findFreePort();
+        if (port == -1) {
+            throw std::runtime_error("could not find free port");
+        }
+    }
+    const auto& paths = engine->getPaths();
+
+    std::vector<std::string> args {
+        "--res", paths.getResourcesFolder().u8string(),
+        "--dir", paths.getUserFilesFolder().u8string(),
+        "--dbg-server",  "tcp:" + std::to_string(port),
+    };
+    platform::new_engine_instance(std::move(args));
+    return lua::pushinteger(L, port);
+}
+
+static int l_focus(lua::State* L) {
+    engine->getWindow().focus();
+    return 0;
+}
+
 static int l_create_memory_device(lua::State* L) {
     std::string name = lua::require_string(L, 1);
     if (io::get_device(name)) {
@@ -54,10 +82,12 @@ static int l_reset_content_sources(lua::State* L) {
 }
 
 const luaL_Reg applib[] = {
+    {"start_debug_instance", lua::wrap<l_start_debug_instance>},
+    {"focus", lua::wrap<l_focus>},
     {"create_memory_device", lua::wrap<l_create_memory_device>},
     {"get_content_sources", lua::wrap<l_get_content_sources>},
     {"set_content_sources", lua::wrap<l_set_content_sources>},
     {"reset_content_sources", lua::wrap<l_reset_content_sources>},
-    // see libcore.cpp an stdlib.lua
+    // for other functions see libcore.cpp and stdlib.lua
     {nullptr, nullptr}
 };
diff --git a/src/logic/scripting/lua/libs/libcore.cpp b/src/logic/scripting/lua/libs/libcore.cpp
index 8454e5c3..e4d5474c 100644
--- a/src/logic/scripting/lua/libs/libcore.cpp
+++ b/src/logic/scripting/lua/libs/libcore.cpp
@@ -25,6 +25,7 @@
 #include "graphics/ui/gui_util.hpp"
 #include "graphics/ui/GUI.hpp"
 #include "graphics/ui/elements/Menu.hpp"
+#include "window/Window.hpp"
 
 using namespace scripting;
 
@@ -299,6 +300,12 @@ static int l_capture_output(lua::State* L) {
     return 1;
 }
 
+static int l_set_title(lua::State* L) {
+    auto title = lua::require_string(L, 1);
+    engine->getWindow().setTitle(title);
+    return 0;
+}
+
 const luaL_Reg corelib[] = {
     {"blank", lua::wrap<l_blank>},
     {"get_version", lua::wrap<l_get_version>},
@@ -320,5 +327,6 @@ const luaL_Reg corelib[] = {
     {"open_url", lua::wrap<l_open_url>},
     {"quit", lua::wrap<l_quit>},
     {"capture_output", lua::wrap<l_capture_output>},
+    {"set_title", lua::wrap<l_set_title>},
     {nullptr, nullptr}
 };
diff --git a/src/logic/scripting/lua/libs/libgui.cpp b/src/logic/scripting/lua/libs/libgui.cpp
index 6e703104..01bfd0d6 100644
--- a/src/logic/scripting/lua/libs/libgui.cpp
+++ b/src/logic/scripting/lua/libs/libgui.cpp
@@ -173,7 +173,25 @@ static int l_get_line_at(lua::State* L) {
     auto node = get_document_node(L, 1);
     auto position = lua::tointeger(L, 2);
     if (auto box = dynamic_cast<TextBox*>(node.node.get())) {
-        return lua::pushinteger(L, box->getLineAt(position));
+        return lua::pushinteger(L, box->getLineAt(position) + 1);
+    }
+    return 0;
+}
+
+static int l_get_index_by_pos(lua::State* L) {
+    auto node = get_document_node(L, 1);
+    auto position = lua::tovec2(L, 2);
+    if (auto box = dynamic_cast<TextBox*>(node.node.get())) {
+        return lua::pushinteger(L, box->calcIndexAt(position.x, position.y));
+    }
+    return 0;
+}
+
+static int l_get_line_y(lua::State* L) {
+    auto node = get_document_node(L, 1);
+    auto line = lua::tointeger(L, 2);
+    if (auto box = dynamic_cast<TextBox*>(node.node.get())) {
+        return lua::pushinteger(L, box->getLineYOffset(line - 1));
     }
     return 0;
 }
@@ -509,6 +527,12 @@ static int p_get_focused(UINode* node, lua::State* L) {
 static int p_get_line_at(UINode*, lua::State* L) {
     return lua::pushcfunction(L, l_get_line_at);
 }
+static int p_get_index_by_pos(UINode*, lua::State* L) {
+    return lua::pushcfunction(L, l_get_index_by_pos);
+}
+static int p_get_line_y(UINode*, lua::State* L) {
+    return lua::pushcfunction(L, l_get_line_y);
+}
 static int p_get_line_pos(UINode*, lua::State* L) {
     return lua::pushcfunction(L, l_get_line_pos);
 }
@@ -619,6 +643,8 @@ static int l_gui_getattr(lua::State* L) {
             {"edited", p_get_edited},
             {"lineNumbers", p_get_line_numbers},
             {"lineAt", p_get_line_at},
+            {"indexByPos", p_get_index_by_pos},
+            {"lineY", p_get_line_y},
             {"linePos", p_get_line_pos},
             {"syntax", p_get_syntax},
             {"markup", p_get_markup},
diff --git a/src/logic/scripting/lua/libs/libinput.cpp b/src/logic/scripting/lua/libs/libinput.cpp
index eb605671..28f87f3c 100644
--- a/src/logic/scripting/lua/libs/libinput.cpp
+++ b/src/logic/scripting/lua/libs/libinput.cpp
@@ -50,8 +50,11 @@ static int l_add_callback(lua::State* L) {
             handler = input.addKeyCallback(key, actual_callback);
         }
     }
-    auto callback = [&gui, actual_callback]() -> bool {
-        if (!gui.isFocusCaught()) {
+
+    bool isTopLevel = lua::toboolean(L, 4);
+
+    auto callback = [&gui, actual_callback, isTopLevel]() -> bool {
+        if (isTopLevel || !gui.isFocusCaught()) {
             return actual_callback();
         }
         return false;
diff --git a/src/logic/scripting/lua/libs/libnetwork.cpp b/src/logic/scripting/lua/libs/libnetwork.cpp
index 580176cd..b1b3a41f 100644
--- a/src/logic/scripting/lua/libs/libnetwork.cpp
+++ b/src/logic/scripting/lua/libs/libnetwork.cpp
@@ -410,7 +410,11 @@ static int l_get_total_download(lua::State* L, network::Network& network) {
 }
 
 static int l_find_free_port(lua::State* L, network::Network& network) {
-    return lua::pushinteger(L, network.findFreePort());
+    int port = network.findFreePort();
+    if (port == -1) {
+        return 0;
+    }
+    return lua::pushinteger(L, port);
 }
 
 static int l_set_nodelay(lua::State* L, network::Network& network) {
diff --git a/src/logic/scripting/lua/lua_extensions.cpp b/src/logic/scripting/lua/lua_extensions.cpp
index 27b47fae..a7de3fdd 100644
--- a/src/logic/scripting/lua/lua_extensions.cpp
+++ b/src/logic/scripting/lua/lua_extensions.cpp
@@ -309,14 +309,15 @@ static int l_debug_sendvalue(lua::State* L) {
 
         lua::pushnil(L);
         while (lua::next(L, 1)) {
-            auto key = lua::tolstring(L, -2);
+            lua::pushvalue(L, -2);
 
-            int type = lua::type(L, -1);
+            auto key = lua::tolstring(L, -1);
+            int type = lua::type(L, -2);
             table[std::string(key)] = dv::object({
                 {"type", std::string(lua::type_name(L, type))},
-                {"short", get_short_value(L, -1, type)},
+                {"short", get_short_value(L, -2, type)},
             });
-            lua::pop(L);
+            lua::pop(L, 2);
         }
         lua::pop(L);
         value = std::move(table);
diff --git a/src/window/Window.hpp b/src/window/Window.hpp
index 71004470..f5a50a73 100644
--- a/src/window/Window.hpp
+++ b/src/window/Window.hpp
@@ -36,6 +36,9 @@ public:
     virtual void setMode(WindowMode mode) = 0;
     virtual WindowMode getMode() const = 0;
 
+    virtual void focus() = 0;
+
+    virtual void setTitle(const std::string& title) = 0;
     virtual void setIcon(const ImageData* image) = 0;
 
     virtual void pushScissor(glm::vec4 area) = 0;
diff --git a/src/window/detail/GLFWWindow.cpp b/src/window/detail/GLFWWindow.cpp
index a80c10e0..07469306 100644
--- a/src/window/detail/GLFWWindow.cpp
+++ b/src/window/detail/GLFWWindow.cpp
@@ -188,7 +188,7 @@ public:
         codepoints.clear();
         pressedKeys.clear();
         if (waitForRefresh) {
-            glfwWaitEvents();
+            glfwWaitEventsTimeout(0.5);
         } else {
             glfwPollEvents();
         }
@@ -468,6 +468,14 @@ public:
         return mode;
     }
 
+    void focus() override {
+        glfwFocusWindow(window);
+    }
+
+    void setTitle(const std::string& title) override {
+        glfwSetWindowTitle(window, title.c_str());
+    }
+
     void setIcon(const ImageData* image) override {
         if (image == nullptr) {
             glfwSetWindowIcon(window, 0, nullptr);