diff --git a/lib/cyberarm_engine/ui/element.rb b/lib/cyberarm_engine/ui/element.rb
index 0bc11c4..82d3254 100644
--- a/lib/cyberarm_engine/ui/element.rb
+++ b/lib/cyberarm_engine/ui/element.rb
@@ -331,8 +331,7 @@ module CyberarmEngine
     end
 
     def debug_draw
-      # FIXME
-      return# if const_defined?(GUI_DEBUG_ONLY_ELEMENT) && self.class == GUI_DEBUG_ONLY_ELEMENT
+      return if CyberarmEngine.const_defined?("GUI_DEBUG_ONLY_ELEMENT") && self.class == GUI_DEBUG_ONLY_ELEMENT
 
       Gosu.draw_line(
         x, y, @debug_color,
@@ -350,7 +349,7 @@ module CyberarmEngine
         Float::INFINITY
       )
       Gosu.draw_line(
-        x, outer_height, @debug_color,
+        x, y + outer_height, @debug_color,
         x, y, @debug_color,
         Float::INFINITY
       )
diff --git a/lib/cyberarm_engine/ui/elements/slider.rb b/lib/cyberarm_engine/ui/elements/slider.rb
index b2b9f6c..5422d44 100644
--- a/lib/cyberarm_engine/ui/elements/slider.rb
+++ b/lib/cyberarm_engine/ui/elements/slider.rb
@@ -33,7 +33,7 @@ module CyberarmEngine
         end
       end
 
-      attr_reader :step_size, :value
+      attr_reader :value
       attr_accessor :range, :step_size
 
       def initialize(options = {}, block = nil)
@@ -47,7 +47,7 @@ module CyberarmEngine
         add(@handle)
       end
 
-      def layout
+      def recalculate
         _width = dimensional_size(@style.width, :width)
         _height = dimensional_size(@style.height, :height)
 
@@ -55,7 +55,7 @@ module CyberarmEngine
         @height = _height
 
         position_handle
-        @handle.layout
+        @handle.recalculate
         @handle.update_background
 
         update_background
diff --git a/lib/cyberarm_engine/ui/gui_state.rb b/lib/cyberarm_engine/ui/gui_state.rb
index 45c842a..b52fd8c 100644
--- a/lib/cyberarm_engine/ui/gui_state.rb
+++ b/lib/cyberarm_engine/ui/gui_state.rb
@@ -85,8 +85,7 @@ module CyberarmEngine
         @tip.draw
       end
 
-      # FIXME
-      if false# defined?(GUI_DEBUG)
+      if CyberarmEngine.const_defined?("GUI_DEBUG")
         Gosu.flush
 
         @root_container.debug_draw