diff --git a/glfw-group.cabal b/glfw-group.cabal
--- a/glfw-group.cabal
+++ b/glfw-group.cabal
@@ -5,7 +5,7 @@
 -- see: https://github.com/sol/hpack
 
 name:           glfw-group
-version:        0.1.0.4
+version:        0.1.0.5
 synopsis:       GLFW package with window groups destroyed together
 description:    Please see the README on GitHub at <https://github.com/YoshikuniJujo/glfw-group#readme>
 category:       Graphics
diff --git a/src/Graphics/UI/GlfwG.hs b/src/Graphics/UI/GlfwG.hs
--- a/src/Graphics/UI/GlfwG.hs
+++ b/src/Graphics/UI/GlfwG.hs
@@ -7,11 +7,17 @@
 
 module Graphics.UI.GlfwG (
 
-	init, setErrorCallback, ErrorCallback, ErrorMessage,
+	-- * INIT AND ERROR
 
-	GlfwB.vulkanSupported, getRequiredInstanceExtensions,
+	init, setErrorCallback, ErrorCallback, GlfwB.Error, ErrorMessage,
 
-	GlfwB.pollEvents, GlfwB.waitEvents
+	-- * EVENT
+
+	GlfwB.pollEvents, GlfwB.waitEvents,
+
+	-- * VULKAN
+
+	GlfwB.vulkanSupported, getRequiredInstanceExtensions,
 
 	) where