Challenge 4 - Colour buttons

[Scout]

Code:

Red = 0
Green = 0
Blue = 0
BG = GraphicsWindow.GetColorFromRGB(Red,Green,Blue)
GraphicsWindow.BackgroundColor = BG
RedColor = GraphicsWindow.GetColorFromRGB(Red,0,0)
GraphicsWindow.BrushColor = RedColor
ButtonRed = Controls.AddButton("",10,10)
Controls.SetButtonCaption(ButtonRed, Red)
GreenColor = GraphicsWindow.GetColorFromRGB(0,Green,0)
GraphicsWindow.BrushColor = GreenColor
ButtonGreen = Controls.AddButton("",110,10)
Controls.SetButtonCaption(ButtonGreen, Green)
BlueColor = GraphicsWindow.GetColorFromRGB(0,0,Blue)
GraphicsWindow.BrushColor = BlueColor
ButtonBlue = Controls.AddButton("",210,10)
Controls.SetButtonCaption(ButtonBlue, Blue)
Controls.ButtonClicked = OnButtonClicked

Sub OnButtonClicked
If Controls.LastClickedButton = ButtonRed then
   Controls.Remove(ButtonRed)
   Red = Math.GetRandomNumber(255)
   RedColor = GraphicsWindow.GetColorFromRGB(Red,0,0)
   GraphicsWindow.BrushColor = RedColor
   ButtonRed = Controls.AddButton("",10,10)
   Controls.SetButtonCaption(ButtonRed, Red) 
Elseif Controls.LastClickedButton = ButtonGreen then
   Controls.Remove(ButtonGreen)
   Green = Math.GetRandomNumber(255)
   GreenColor = GraphicsWindow.GetColorFromRGB(0,Green,0)
   GraphicsWindow.BrushColor = GreenColor
   ButtonGreen = Controls.AddButton("",110,10)
   Controls.SetButtonCaption(ButtonGreen, Green)
Elseif Controls.LastClickedButton = ButtonBlue then
   Controls.Remove(ButtonBlue)
   Blue = Math.GetRandomNumber(255)
   BlueColor = GraphicsWindow.GetColorFromRGB(0,0,Blue)
   GraphicsWindow.BrushColor = BlueColor
   ButtonBlue = Controls.AddButton("",210,10)
   Controls.SetButtonCaption(ButtonBlue, Blue)
EndIf
BG = GraphicsWindow.GetColorFromRGB(Red,Green,Blue)
GraphicsWindow.BackgroundColor = BG
  TBox = Controls.AddTextBox(200,200)
  Controls.SetTextBoxText(TBox, TBox)
TextWindow.WriteLine(ButtonRed + "    " + ButtonGreen + "    " + ButtonBlue)
EndSub