diff --git a/src/app/CMakeLists.txt b/src/app/CMakeLists.txt
index bfb712ac4..5791b59df 100644
--- a/src/app/CMakeLists.txt
+++ b/src/app/CMakeLists.txt
@@ -154,6 +154,7 @@ if(ENABLE_SCRIPTING)
     script/cel_class.cpp
     script/cels_class.cpp
     script/color_class.cpp
+    script/dialog_class.cpp
     script/engine.cpp
     script/frame_class.cpp
     script/frames_class.cpp
diff --git a/src/app/app.cpp b/src/app/app.cpp
index 86027303b..d23060d6a 100644
--- a/src/app/app.cpp
+++ b/src/app/app.cpp
@@ -392,6 +392,11 @@ App::~App()
     LOG("APP: Exit\n");
     ASSERT(m_instance == this);
 
+#ifdef ENABLE_SCRIPTING
+    // Destroy scripting engine
+    m_engine.reset(nullptr);
+#endif
+
     // Delete file formats.
     FileFormatsManager::destroyInstance();
 
diff --git a/src/app/script/color_class.cpp b/src/app/script/color_class.cpp
index 62a4d6031..370793d4e 100644
--- a/src/app/script/color_class.cpp
+++ b/src/app/script/color_class.cpp
@@ -18,7 +18,7 @@ namespace script {
 
 namespace {
 
-Color Color_new(lua_State* L, int index)
+app::Color Color_new(lua_State* L, int index)
 {
   app::Color color;
   // Copy other color
diff --git a/src/app/script/dialog_class.cpp b/src/app/script/dialog_class.cpp
new file mode 100644
index 000000000..464609dc3
--- /dev/null
+++ b/src/app/script/dialog_class.cpp
@@ -0,0 +1,602 @@
+// Aseprite
+// Copyright (C) 2018  David Capello
+//
+// This program is distributed under the terms of
+// the End-User License Agreement for Aseprite.
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "app/app.h"
+#include "app/color.h"
+#include "app/color_utils.h"
+#include "app/script/engine.h"
+#include "app/script/luacpp.h"
+#include "app/ui/color_button.h"
+#include "app/ui/expr_entry.h"
+#include "ui/box.h"
+#include "ui/button.h"
+#include "ui/combobox.h"
+#include "ui/entry.h"
+#include "ui/grid.h"
+#include "ui/label.h"
+#include "ui/separator.h"
+#include "ui/slider.h"
+#include "ui/window.h"
+
+#include <map>
+
+namespace app {
+namespace script {
+
+using namespace ui;
+
+namespace {
+
+struct Dialog {
+  ui::Window window;
+  ui::VBox vbox;
+  ui::Grid grid;
+  ui::HBox* hbox = nullptr;
+  std::map<std::string, ui::Widget*> dataWidgets;
+  int currentRadioGroup = 0;
+
+  // Used to create a new row when a different kind of widget is added
+  // in the dialog.
+  ui::WidgetType lastWidgetType = ui::kGenericWidget;
+
+  // Used to keep a reference to the last onclick button pressed, so
+  // then Dialog.data returns true for the button that closed the
+  // dialog.
+  ui::Widget* lastButton = nullptr;
+
+  // Reference used to keep the dialog alive (so it's not garbage
+  // collected) when it's visible.
+  int showRef = LUA_REFNIL;
+  lua_State* L = nullptr;
+
+  // A reference to a table with pointers to functions for events
+  // (e.g. onclick callbacks).
+  int callbacksTableRef = LUA_REFNIL;
+
+  Dialog()
+    : window(ui::Window::WithTitleBar, "Script"),
+      grid(2, false) {
+    window.addChild(&grid);
+    window.Close.connect([this](ui::CloseEvent&){ unrefShow(); });
+  }
+
+  void refShow(lua_State* L) {
+    if (showRef == LUA_REFNIL) {
+      this->L = L;
+      lua_pushvalue(L, 1);
+      showRef = luaL_ref(L, LUA_REGISTRYINDEX);
+    }
+  }
+
+  void unrefShow() {
+    if (showRef != LUA_REFNIL) {
+      luaL_unref(this->L, LUA_REGISTRYINDEX, showRef);
+      showRef = LUA_REFNIL;
+      L = nullptr;
+    }
+  }
+};
+
+int Dialog_new(lua_State* L)
+{
+  auto dlg = push_new<Dialog>(L);
+  if (lua_isstring(L, 1))
+    dlg->window.setText(lua_tostring(L, 1));
+
+  lua_newtable(L);
+#if 0 // Make values in callbacksTableRef table weak. (Weak references
+      // are lost for onclick= events with local functions when we use
+      // showInBackground() and we left the script scope)
+  {
+    lua_newtable(L);
+    lua_pushstring(L, "v");
+    lua_setfield(L, -2, "__mode");
+    lua_setmetatable(L, -2);
+  }
+#endif
+  dlg->callbacksTableRef = luaL_ref(L, LUA_REGISTRYINDEX);
+  return 1;
+}
+
+int Dialog_gc(lua_State* L)
+{
+  auto dlg = get_obj<Dialog>(L, 1);
+  luaL_unref(L, LUA_REGISTRYINDEX, dlg->callbacksTableRef);
+  dlg->~Dialog();
+  return 0;
+}
+
+int Dialog_show(lua_State* L)
+{
+  auto dlg = get_obj<Dialog>(L, 1);
+  dlg->refShow(L);
+
+  bool wait = true;
+  if (lua_istable(L, 2)) {
+    int type = lua_getfield(L, 2, "wait");
+    if (type == LUA_TBOOLEAN)
+      wait = lua_toboolean(L, -1);
+    lua_pop(L, 1);
+  }
+
+  if (wait)
+    dlg->window.openWindowInForeground();
+  else
+    dlg->window.openWindow();
+
+  lua_pushvalue(L, 1);
+  return 1;
+}
+
+int Dialog_close(lua_State* L)
+{
+  auto dlg = get_obj<Dialog>(L, 1);
+  dlg->window.closeWindow(nullptr);
+  lua_pushvalue(L, 1);
+  return 1;
+}
+
+int Dialog_add_widget(lua_State* L, Widget* widget)
+{
+  auto dlg = get_obj<Dialog>(L, 1);
+  const char* label = nullptr;
+
+  // This is to separate different kind of widgets without label in
+  // different rows.
+  if (dlg->lastWidgetType != widget->type()) {
+    dlg->lastWidgetType = widget->type();
+    dlg->hbox = nullptr;
+  }
+
+  if (lua_istable(L, 2)) {
+    // Widget ID (used to fill the Dialog_get_data table then)
+    int type = lua_getfield(L, 2, "id");
+    if (type == LUA_TSTRING) {
+      if (auto id = lua_tostring(L, -1)) {
+        widget->setId(id);
+        dlg->dataWidgets[id] = widget;
+      }
+    }
+    lua_pop(L, 1);
+
+    // Label
+    type = lua_getfield(L, 2, "label");
+    if (type == LUA_TSTRING)
+      label = lua_tostring(L, -1);
+    lua_pop(L, 1);
+  }
+
+  if (label || !dlg->hbox) {
+    if (label)
+      dlg->grid.addChildInCell(new ui::Label(label), 1, 1, ui::LEFT | ui::TOP);
+    else
+      dlg->grid.addChildInCell(new ui::HBox, 1, 1, ui::LEFT | ui::TOP);
+
+    auto hbox = new ui::HBox;
+    if (widget->type() == ui::kButtonWidget)
+      hbox->enableFlags(ui::HOMOGENEOUS);
+    dlg->grid.addChildInCell(hbox, 1, 1, ui::HORIZONTAL | ui::TOP);
+    dlg->hbox = hbox;
+  }
+
+  widget->setExpansive(true);
+  dlg->hbox->addChild(widget);
+
+  lua_pushvalue(L, 1);
+  return 1;
+}
+
+int Dialog_newrow(lua_State* L)
+{
+  auto dlg = get_obj<Dialog>(L, 1);
+  dlg->hbox = nullptr;
+  lua_pushvalue(L, 1);
+  return 1;
+}
+
+int Dialog_separator(lua_State* L)
+{
+  auto dlg = get_obj<Dialog>(L, 1);
+
+  std::string text;
+  if (lua_isstring(L, 2)) {
+    if (auto p = lua_tostring(L, 2))
+      text = p;
+  }
+  else if (lua_istable(L, 2)) {
+    int type = lua_getfield(L, 2, "text");
+    if (type == LUA_TSTRING) {
+      if (auto p = lua_tostring(L, -1))
+        text = p;
+    }
+    lua_pop(L, 1);
+  }
+
+  auto widget = new ui::Separator(text, ui::HORIZONTAL);
+  dlg->grid.addChildInCell(widget, 2, 1, ui::HORIZONTAL | ui::TOP);
+  dlg->hbox = nullptr;
+
+  lua_pushvalue(L, 1);
+  return 1;
+}
+
+int Dialog_label(lua_State* L)
+{
+  std::string text;
+  if (lua_istable(L, 2)) {
+    int type = lua_getfield(L, 2, "text");
+    if (type == LUA_TSTRING) {
+      if (auto p = lua_tostring(L, -1))
+        text = p;
+    }
+    lua_pop(L, 1);
+  }
+
+  auto widget = new ui::Label(text.c_str());
+  return Dialog_add_widget(L, widget);
+}
+
+template<typename T>
+int Dialog_button_base(lua_State* L, T** outputWidget = nullptr)
+{
+  auto dlg = get_obj<Dialog>(L, 1);
+
+  std::string text;
+  if (lua_istable(L, 2)) {
+    int type = lua_getfield(L, 2, "text");
+    if (type == LUA_TSTRING) {
+      if (auto p = lua_tostring(L, -1))
+        text = p;
+    }
+    lua_pop(L, 1);
+  }
+
+  auto widget = new T(text.c_str());
+  if (outputWidget)
+    *outputWidget = widget;
+
+  widget->processMnemonicFromText();
+
+  bool closeWindowByDefault = (widget->type() == ui::kButtonWidget);
+
+  if (lua_istable(L, 2)) {
+    int type = lua_getfield(L, 2, "selected");
+    if (type != LUA_TNONE)
+      widget->setSelected(lua_toboolean(L, -1));
+    lua_pop(L, 1);
+
+    type = lua_getfield(L, 2, "onclick");
+    if (type == LUA_TFUNCTION) {
+      // Add a reference to the onclick function
+      const int ref = dlg->callbacksTableRef;
+      lua_rawgeti(L, LUA_REGISTRYINDEX, ref);
+      lua_len(L, -1);
+      const int n = 1+lua_tointegerx(L, -1, nullptr);
+      lua_pop(L, 1);
+      lua_pushvalue(L, -2);     // Copy the function in onclick
+      lua_seti(L, -2, n);       // Put the copy of the function in the callbacksTableRef
+      widget->Click.connect(
+        [dlg, widget, L, ref, n](ui::Event& ev) {
+          dlg->lastButton = widget;
+
+          lua_rawgeti(L, LUA_REGISTRYINDEX, ref);
+          lua_geti(L, -1, n);
+
+          if (lua_isfunction(L, -1))
+            lua_call(L, 0, 0);
+          else
+            lua_pop(L, 1);
+          lua_pop(L, 1);        // Pop table from the registry
+        });
+      closeWindowByDefault = false;
+    }
+    lua_pop(L, 1);
+  }
+
+  if (closeWindowByDefault)
+    widget->Click.connect([widget](ui::Event&){ widget->closeWindow(); });
+
+  return Dialog_add_widget(L, widget);
+}
+
+int Dialog_button(lua_State* L)
+{
+  return Dialog_button_base<ui::Button>(L);
+}
+
+int Dialog_check(lua_State* L)
+{
+  return Dialog_button_base<ui::CheckBox>(L);
+}
+
+int Dialog_radio(lua_State* L)
+{
+  ui::RadioButton* radio = nullptr;
+  const int res = Dialog_button_base<ui::RadioButton>(L, &radio);
+  if (radio) {
+    auto dlg = get_obj<Dialog>(L, 1);
+    bool hasLabelField = false;
+
+    if (lua_istable(L, 2)) {
+      int type = lua_getfield(L, 2, "label");
+      if (type == LUA_TSTRING)
+        hasLabelField = true;
+      lua_pop(L, 1);
+    }
+
+    if (dlg->currentRadioGroup == 0 ||
+        hasLabelField) {
+      ++dlg->currentRadioGroup;
+    }
+
+    radio->setRadioGroup(dlg->currentRadioGroup);
+  }
+  return res;
+}
+
+int Dialog_entry(lua_State* L)
+{
+  std::string text;
+  if (lua_istable(L, 2)) {
+    int type = lua_getfield(L, 2, "text");
+    if (type == LUA_TSTRING) {
+      if (auto p = lua_tostring(L, -1))
+        text = p;
+    }
+    lua_pop(L, 1);
+  }
+
+  auto widget = new ui::Entry(4096, text.c_str());
+  return Dialog_add_widget(L, widget);
+}
+
+int Dialog_number(lua_State* L)
+{
+  auto widget = new ExprEntry;
+
+  if (lua_istable(L, 2)) {
+    int type = lua_getfield(L, 2, "text");
+    if (type == LUA_TSTRING) {
+      if (auto p = lua_tostring(L, -1))
+        widget->setText(p);
+    }
+    lua_pop(L, 1);
+
+    type = lua_getfield(L, 2, "decimals");
+    if (type != LUA_TNONE &&
+        type != LUA_TNIL) {
+      widget->setDecimals(lua_tointegerx(L, -1, nullptr));
+    }
+    lua_pop(L, 1);
+  }
+
+  return Dialog_add_widget(L, widget);
+}
+
+int Dialog_slider(lua_State* L)
+{
+  int min = 0;
+  int max = 100;
+  int value = 100;
+
+  if (lua_istable(L, 2)) {
+    int type = lua_getfield(L, 2, "min");
+    if (type != LUA_TNONE) {
+      min = lua_tointegerx(L, -1, nullptr);
+    }
+    lua_pop(L, 1);
+
+    type = lua_getfield(L, 2, "max");
+    if (type != LUA_TNONE) {
+      max = lua_tointegerx(L, -1, nullptr);
+    }
+    lua_pop(L, 1);
+
+    type = lua_getfield(L, 2, "value");
+    if (type != LUA_TNONE) {
+      value = lua_tointegerx(L, -1, nullptr);
+    }
+    lua_pop(L, 1);
+  }
+
+  auto widget = new ui::Slider(min, max, value);
+  return Dialog_add_widget(L, widget);
+}
+
+int Dialog_combobox(lua_State* L)
+{
+  auto widget = new ui::ComboBox;
+
+  if (lua_istable(L, 2)) {
+    int type = lua_getfield(L, 2, "options");
+    if (type == LUA_TTABLE) {
+      lua_pushnil(L);
+      while (lua_next(L, -2) != 0) {
+        if (auto p = lua_tostring(L, -1))
+          widget->addItem(p);
+        lua_pop(L, 1);
+      }
+    }
+    lua_pop(L, 1);
+
+    type = lua_getfield(L, 2, "option");
+    if (type == LUA_TSTRING) {
+      if (auto p = lua_tostring(L, -1)) {
+        int index = widget->findItemIndex(p);
+        if (index >= 0)
+          widget->setSelectedItemIndex(index);
+      }
+    }
+    lua_pop(L, 1);
+  }
+
+  return Dialog_add_widget(L, widget);
+}
+
+int Dialog_color(lua_State* L)
+{
+  app::Color color;
+  if (lua_istable(L, 2)) {
+    lua_getfield(L, 2, "color");
+    color = convert_args_into_color(L, -1);
+    lua_pop(L, 1);
+  }
+
+  auto widget = new ColorButton(color,
+                                app_get_current_pixel_format(),
+                                ColorButtonOptions());
+  return Dialog_add_widget(L, widget);
+}
+
+int Dialog_get_data(lua_State* L)
+{
+  auto dlg = get_obj<Dialog>(L, 1);
+  lua_newtable(L);
+  for (const auto& kv : dlg->dataWidgets) {
+    const ui::Widget* widget = kv.second;
+    switch (widget->type()) {
+      case ui::kButtonWidget:
+      case ui::kCheckWidget:
+      case ui::kRadioWidget:
+        lua_pushboolean(L, widget->isSelected() ||
+                           dlg->window.closer() == widget ||
+                           dlg->lastButton == widget);
+        break;
+      case ui::kEntryWidget:
+        if (auto expr = dynamic_cast<const ExprEntry*>(widget)) {
+          if (expr->decimals() == 0)
+            lua_pushinteger(L, widget->textInt());
+          else
+            lua_pushnumber(L, widget->textDouble());
+        }
+        else {
+          lua_pushstring(L, widget->text().c_str());
+        }
+        break;
+      case ui::kLabelWidget:
+        lua_pushstring(L, widget->text().c_str());
+        break;
+      case ui::kSliderWidget:
+        if (auto slider = dynamic_cast<const ui::Slider*>(widget)) {
+          lua_pushinteger(L, slider->getValue());
+        }
+        break;
+      case ui::kComboBoxWidget:
+        if (auto combobox = dynamic_cast<const ui::ComboBox*>(widget)) {
+          if (auto sel = combobox->getSelectedItem())
+            lua_pushstring(L, sel->text().c_str());
+          else
+            lua_pushnil(L);
+        }
+        break;
+      default:
+        if (auto colorButton = dynamic_cast<const ColorButton*>(widget))
+          push_obj<app::Color>(L, colorButton->getColor());
+        else
+          lua_pushnil(L);
+        break;
+    }
+    lua_setfield(L, -2, kv.first.c_str());
+  }
+  return 1;
+}
+
+int Dialog_set_data(lua_State* L)
+{
+  auto dlg = get_obj<Dialog>(L, 1);
+  if (!lua_istable(L, 2))
+    return 0;
+  for (const auto& kv : dlg->dataWidgets) {
+    lua_getfield(L, 2, kv.first.c_str());
+
+    ui::Widget* widget = kv.second;
+    switch (widget->type()) {
+      case ui::kButtonWidget:
+      case ui::kCheckWidget:
+      case ui::kRadioWidget:
+        widget->setSelected(lua_toboolean(L, -1));
+        break;
+      case ui::kEntryWidget:
+        if (auto expr = dynamic_cast<ExprEntry*>(widget)) {
+          if (expr->decimals() == 0)
+            expr->setTextf("%d", lua_tointeger(L, -1));
+          else
+            expr->setTextf("%.*g", expr->decimals(), lua_tonumber(L, -1));
+        }
+        else if (auto p = lua_tostring(L, -1)) {
+          widget->setText(p);
+        }
+        break;
+      case ui::kLabelWidget:
+        if (auto p = lua_tostring(L, -1)) {
+          widget->setText(p);
+        }
+        break;
+      case ui::kSliderWidget:
+        if (auto slider = dynamic_cast<ui::Slider*>(widget)) {
+          slider->setValue(lua_tointeger(L, -1));
+        }
+        break;
+      case ui::kComboBoxWidget:
+        if (auto combobox = dynamic_cast<ui::ComboBox*>(widget)) {
+          if (auto p = lua_tostring(L, -1)) {
+            int index = combobox->findItemIndex(p);
+            if (index >= 0)
+              combobox->setSelectedItemIndex(index);
+          }
+        }
+        break;
+      default:
+        if (auto colorButton = dynamic_cast<ColorButton*>(widget))
+          colorButton->setColor(convert_args_into_color(L, -1));
+        break;
+    }
+
+    lua_pop(L, 1);
+  }
+  return 1;
+}
+
+const luaL_Reg Dialog_methods[] = {
+  { "__gc", Dialog_gc },
+  { "show", Dialog_show },
+  { "close", Dialog_close },
+  { "newrow", Dialog_newrow },
+  { "separator", Dialog_separator },
+  { "label", Dialog_label },
+  { "button", Dialog_button },
+  { "check", Dialog_check },
+  { "radio", Dialog_radio },
+  { "entry", Dialog_entry },
+  { "number", Dialog_number },
+  { "slider", Dialog_slider },
+  { "combobox", Dialog_combobox },
+  { "color", Dialog_color },
+  { nullptr, nullptr }
+};
+
+const Property Dialog_properties[] = {
+  { "data", Dialog_get_data, Dialog_set_data },
+  { nullptr, nullptr, nullptr }
+};
+
+} // anonymous namespace
+
+DEF_MTNAME(Dialog);
+
+void register_dialog_class(lua_State* L)
+{
+  REG_CLASS(L, Dialog);
+  REG_CLASS_NEW(L, Dialog);
+  REG_CLASS_PROPERTIES(L, Dialog);
+}
+
+} // namespace script
+} // namespace app
diff --git a/src/app/script/engine.cpp b/src/app/script/engine.cpp
index cad49d68a..e77052612 100644
--- a/src/app/script/engine.cpp
+++ b/src/app/script/engine.cpp
@@ -88,6 +88,7 @@ void register_app_command_object(lua_State* L);
 void register_cel_class(lua_State* L);
 void register_cels_class(lua_State* L);
 void register_color_class(lua_State* L);
+void register_dialog_class(lua_State* L);
 void register_frame_class(lua_State* L);
 void register_frames_class(lua_State* L);
 void register_image_class(lua_State* L);
@@ -216,6 +217,7 @@ Engine::Engine()
   register_cel_class(L);
   register_cels_class(L);
   register_color_class(L);
+  register_dialog_class(L);
   register_frame_class(L);
   register_frames_class(L);
   register_image_class(L);
@@ -275,6 +277,9 @@ bool Engine::evalCode(const std::string& code,
     }
   }
   lua_pop(L, 1);
+
+  // Collect script garbage.
+  lua_gc(L, LUA_GCCOLLECT);
   return ok;
 }
 
diff --git a/src/app/ui/expr_entry.h b/src/app/ui/expr_entry.h
index 0929c2b53..6c00d6c86 100644
--- a/src/app/ui/expr_entry.h
+++ b/src/app/ui/expr_entry.h
@@ -17,9 +17,8 @@ namespace app {
   public:
     ExprEntry();
 
-    void setDecimals(int decimals) {
-      m_decimals = decimals;
-    }
+    int decimals() const { return m_decimals; }
+    void setDecimals(int decimals) { m_decimals = decimals; }
 
   protected:
     bool onProcessMessage(ui::Message* msg) override;
diff --git a/src/ui/button.cpp b/src/ui/button.cpp
index bc8b7f41f..1667b9b36 100644
--- a/src/ui/button.cpp
+++ b/src/ui/button.cpp
@@ -1,5 +1,5 @@
 // Aseprite UI Library
-// Copyright (C) 2001-2017  David Capello
+// Copyright (C) 2001-2018  David Capello
 //
 // This file is released under the terms of the MIT license.
 // Read LICENSE.txt for more information.
@@ -22,9 +22,9 @@
 namespace ui {
 
 ButtonBase::ButtonBase(const std::string& text,
-                       WidgetType type,
-                       WidgetType behaviorType,
-                       WidgetType drawType)
+                       const WidgetType type,
+                       const WidgetType behaviorType,
+                       const WidgetType drawType)
   : Widget(type)
   , m_pressedStatus(false)
   , m_behaviorType(behaviorType)
@@ -274,7 +274,8 @@ Button::Button(const std::string& text)
 // CheckBox class
 // ======================================================================
 
-CheckBox::CheckBox(const std::string& text, WidgetType drawType)
+CheckBox::CheckBox(const std::string& text,
+                   const WidgetType drawType)
   : ButtonBase(text, kCheckWidget, kCheckWidget, drawType)
 {
   setAlign(LEFT | MIDDLE);
@@ -284,7 +285,9 @@ CheckBox::CheckBox(const std::string& text, WidgetType drawType)
 // RadioButton class
 // ======================================================================
 
-RadioButton::RadioButton(const std::string& text, int radioGroup, WidgetType drawType)
+RadioButton::RadioButton(const std::string& text,
+                         const int radioGroup,
+                         const WidgetType drawType)
   : ButtonBase(text, kRadioWidget, kRadioWidget, drawType)
 {
   setAlign(LEFT | MIDDLE);
diff --git a/src/ui/button.h b/src/ui/button.h
index 442d6efdb..793bdc96c 100644
--- a/src/ui/button.h
+++ b/src/ui/button.h
@@ -1,5 +1,5 @@
 // Aseprite UI Library
-// Copyright (C) 2001-2017  David Capello
+// Copyright (C) 2001-2018  David Capello
 //
 // This file is released under the terms of the MIT license.
 // Read LICENSE.txt for more information.
@@ -25,9 +25,9 @@ namespace ui {
   class ButtonBase : public Widget {
   public:
     ButtonBase(const std::string& text,
-               WidgetType type,
-               WidgetType behaviorType,
-               WidgetType drawType);
+               const WidgetType type,
+               const WidgetType behaviorType,
+               const WidgetType drawType);
     virtual ~ButtonBase();
 
     WidgetType behaviorType() const;
@@ -60,13 +60,16 @@ namespace ui {
   // Check boxes
   class CheckBox : public ButtonBase {
   public:
-    CheckBox(const std::string& text, WidgetType drawType = kCheckWidget);
+    CheckBox(const std::string& text,
+             const WidgetType drawType = kCheckWidget);
   };
 
   // Radio buttons
   class RadioButton : public ButtonBase {
   public:
-    RadioButton(const std::string& text, int radioGroup, WidgetType drawType = kRadioWidget);
+    RadioButton(const std::string& text,
+                const int radioGroup = 0,
+                const WidgetType drawType = kRadioWidget);
 
     int getRadioGroup() const;
     void setRadioGroup(int radioGroup);