Copy&Paste-Fehler meinerseits.
Code: 
## Skillmenu requested by user
## Author: D.T. Linkey
## Date: 03.03.2018

module LDT_SKILL_MENU
  #Confirmation texts
  CONFIRM_TITLE = " aufwerten?"
  CONFIRM_TRUE = "Ja"
  CONFIRM_FALSE = "Nein"
  #Headline/Title
  SKILL_TITLE = "Skillpunkte insg."
  #skill names ( array can be used to display different Names per Level)
  SKILL_NAMES = ["Skillname1", #skill 1
                "Skillname2",  #skill 2
                ["Skillname3 St0","Skillname3 St1","Skillname3 MAX"],#skill 3
                "Skillname4"]  #skill 4
  #skill icon ids ( array can be used to display different Icons per Level)
  ICON_IDS = [4, #skill 1
              [8,10,11,12], #skill 2
              9, #skill 3
              26] #skill 4
  #skill costs
  SKILL_COSTS = [[3,7,11,24,49,-1],
                 [3,15,33,-1],
                 [4,60,-1],
                 [7,23,59,-1]]
  #variable for each skill (e.g. 1 = $game_variables[1])
  SKILL_VARS = [1,2,3,4]
  #variable for each skillcosts (e.g. 1 = $game_variables[1])
  COST_VARS = [5,6,7,8]
  #variable for total skill points (e.g. 1 = $game_variables[1])
  SKILL_TOTAL_POINT_VAR = 9
    
  #Symbol displayed if max Level is reached
  MAX_LEVEL_SIGN = "-"
  #Graphics
  #Start position vertical (0 = top, 480 = botton)
  G_START_Y = 0
  #start position horizontal (0 = left, 640 = right)
  G_START_X = 0
  #Width of the first Window
  G_WIDTH_1 = 280
  #Width of the second Window
  G_WIDTH_2 = 240
  #Confirmation window alignment (1 = horiz., 2= vert.)
  G_CONFIRM_ALIGN = 2
end

class LDT_Skill_Scene < Scene_Base
  def start
    super
    create_title_window
    create_skill_window
    create_confirmation_windows
    create_background
  end
  
  def create_title_window()
    @title_window = LDT_Skill_Window_Title.new(LDT_SKILL_MENU::G_START_X,LDT_SKILL_MENU::G_START_Y,1,LDT_SKILL_MENU::G_WIDTH_1)
    @title_window.set_text(LDT_SKILL_MENU::SKILL_TITLE)
  end
  
  def create_skill_window()
    ty = LDT_SKILL_MENU::G_START_Y + @title_window.height
    th = LDT_SKILL_MENU::SKILL_NAMES.size * 24 + 32
    @skill_window = LDT_Skill_Window.new(LDT_SKILL_MENU::G_START_X,ty,LDT_SKILL_MENU::G_WIDTH_1,th)
    @skill_window.viewport = @viewport

    @skill_window.set_handler(:ok,     method(:on_menu_ok))
    @skill_window.set_handler(:cancel, method(:return_scene))
    @skill_window.activate    
    @skill_window.select(0)
    @skill_window.show
  end
  
  def create_background
    @background_sprite = Sprite.new
    @background_sprite.bitmap = SceneManager.background_bitmap
    @background_sprite.color.set(16, 16, 16, 128)
  end
  
  def create_confirmation_windows()
    if(LDT_SKILL_MENU::G_CONFIRM_ALIGN == 1)
      tx = LDT_SKILL_MENU::G_START_X + LDT_SKILL_MENU::G_WIDTH_1
      ty = LDT_SKILL_MENU::G_START_Y
    else
      tx = LDT_SKILL_MENU::G_START_X
      ty = LDT_SKILL_MENU::G_START_Y + @title_window.height + @skill_window.height
    end
    @confirm_title_window = LDT_Confirm_Window_Title.new(tx,ty,1,LDT_SKILL_MENU::G_WIDTH_2)
    @confirm_title_window.set_text("")
    @confirm_title_window.hide
    
    th = 2 * 24 + 32
    ty = ty + @confirm_title_window.height
    @confirm_window = LDT_Skill_Window_Confirmation.new(tx,ty,LDT_SKILL_MENU::G_WIDTH_2,th)
    @confirm_window.viewport = @viewport
    @confirm_window.set_handler(:ok,     method(:on_conf_ok))
    @confirm_window.set_handler(:cancel, method(:on_conf_cancel))
    @confirm_window.hide
  end
  
  def on_menu_ok
    ti = @skill_window.index
    if(@skill_window.current_item_enabled?)
      ttext = get_skill_name(ti) + LDT_SKILL_MENU::CONFIRM_TITLE
      @confirm_title_window.set_text(ttext)
      @confirm_title_window.show
      
      @confirm_window.activate
      @confirm_window.select(0)
      @confirm_window.show
    else
      @skill_window.activate
    end
  end
  
  def on_conf_ok
    if(@confirm_window.index >= 1)
      on_conf_cancel
    else
      ti = @skill_window.index
      $game_variables[LDT_SKILL_MENU::SKILL_VARS[ti]] += 1
      $game_variables[LDT_SKILL_MENU::SKILL_TOTAL_POINT_VAR] -= $game_variables[LDT_SKILL_MENU::COST_VARS[ti]]
      refresh_windows
      on_conf_cancel
    end
  end
  
  def refresh_windows
    @skill_window.refresh
    @title_window.refresh
  end
  
  def on_conf_cancel
    @confirm_window.deactivate
    @confirm_window.hide
    @confirm_title_window.hide
    @skill_window.activate
  end
  
  def get_skill_name(index)
    tskill = LDT_SKILL_MENU::SKILL_NAMES[index]
    if(tskill.is_a?(Array))
      return tskill[$game_variables[LDT_SKILL_MENU::SKILL_VARS[index]]]
    else
      return tskill
    end
  end
end

class LDT_Skill_Window < Window_Selectable

  def initialize(x, y, width, height)
    super(x,y,width,height)
    @skills = LDT_SKILL_MENU::SKILL_NAMES
    refresh
  end
  
  def item_max
    @skills ? @skills.size : 1
  end

  def item
    @skills && index >= 0 ? @skills[index] : nil
  end
  
  def refresh
    set_costs()
    create_contents
    draw_all_items
  end

  
  def draw_item(index)
      rect = item_rect(index)
      rect.width -= 4
      if(current_item_enabled?(index))
        contents.font.color.alpha = 255
      else
        contents.font.color.alpha = translucent_alpha
      end
      
      draw_icon(get_icon_num(index), rect.x, rect.y, current_item_enabled?(index))
      draw_text(rect.x + 26, rect.y, rect.width - 26, rect.height, get_skill_name(index))#, rect.x, rect.y)
      draw_text(rect,get_costs(index),2)
  end
    
  def get_icon_num(index)
    ticon = LDT_SKILL_MENU::ICON_IDS[index]
    if(ticon.is_a?(Array))
      return ticon[$game_variables[LDT_SKILL_MENU::SKILL_VARS[index]]]
    else
      return ticon
    end
  end
  
  def get_skill_name(index)
    if(@skills[index].is_a?(Array))
      return @skills[index][$game_variables[LDT_SKILL_MENU::SKILL_VARS[index]]]
    else
      return @skills[index]
    end
  end
    
  def set_costs()
    LDT_SKILL_MENU::COST_VARS.each_with_index do |tcv,ti|
      tskill = $game_variables[LDT_SKILL_MENU::SKILL_VARS[ti]]
      $game_variables[tcv] = LDT_SKILL_MENU::SKILL_COSTS[ti][tskill]
    end
  end
  
  def current_item_enabled?(tindex = index)
    return false if(tindex < 0)
    tc = get_costs(tindex)
    return false if(tc == LDT_SKILL_MENU::MAX_LEVEL_SIGN)
    return ($game_variables[LDT_SKILL_MENU::SKILL_TOTAL_POINT_VAR] >= tc)
  end
  
  def get_costs(index)
    tcosts = $game_variables[LDT_SKILL_MENU::COST_VARS[index]]
    return tcosts >= 0 ? tcosts : LDT_SKILL_MENU::MAX_LEVEL_SIGN
  end
end

class LDT_Skill_Window_Confirmation < Window_Selectable
   def initialize(x, y, width, height)
    super(x,y,width,height)
    @items = [LDT_SKILL_MENU::CONFIRM_TRUE,LDT_SKILL_MENU::CONFIRM_FALSE]
    refresh
  end
  
  def item_max
    @items ? @items.size : 1
  end

  def item
    @items && index >= 0 ? @items[index] : nil
  end
  
  def refresh
    create_contents
    draw_all_items
  end

  
  def draw_item(index)
    rect = item_rect(index)
    rect.width -= 4
    draw_text(rect,get_item_name(index))
  end
    
  def get_item_name(index)
    return @items[index]
  end
    
  def get_costs(index)
    return $game_variables[LDT_SKILL_MENU::COST_VARS[index]]
  end
end
  

class LDT_Skill_Window_Title < Window_Base

  def initialize(x,y,line_number = 1, tw = nil)
    tw = (tw ? tw : Graphics.width)
    super(x, y, tw, fitting_height(line_number))
  end
  
  def refresh
    contents.clear
    draw_text_ex(4, 0, @text)
    draw_text(4, 0, width - 32, line_height, get_second_text(), 2)
  end

  def get_second_text()
    return $game_variables[LDT_SKILL_MENU::SKILL_TOTAL_POINT_VAR]
  end
  
  def set_text(text)
    if text != @text
      @text = text
      refresh
    end
  end
end

class LDT_Confirm_Window_Title < Window_Base

  def initialize(x,y,line_number = 1, tw = nil)
    tw = (tw ? tw : Graphics.width)
    super(x, y, tw, fitting_height(line_number))
    @text2 = ""
  end
  
  def refresh
    contents.clear
    draw_text_ex(4, 0, @text)
  end
  
  def set_text(text)
    if text != @text
      @text = text
      refresh
    end
  end
end