[Lua][Help][Menu] Not showing change in selection

-- -- TechOS -- --

-- Local Variables --

local nScreenWidth, nScreenHeight = term.getSize()
local nSelection = 1
local menustate = "Boot"

-- End Local Variables --

-- Local Tables --

local tMenus = {
  [ "Boot" ] = {
	options = { "Inventory", "Turtles", "Reactor" },
	draw = drawBoot
  },
  [ "Inventory" ] = {
	options = { "Raw Materials", "Refined Materials" },
	draw = drawInventory
  },
  [ "Turtles" ] = {
	options = { "Mining" },
	draw = drawTurtles },
  [ "Reactor" ] = {
	options = { "Control" },
	draw = drawReactor
  }
}

-- End Local Tables --

-- -- Draw Functions -- --

-- Base Draw Functios --

function ClearScreen()
  term.clear()
  term.setCursorPos( 1, 1 )
end

function PrintCentered( nHeight, sString )
  term.setCursorPos( nScreenWidth/2 - #sString/2, nHeight )
  term.write( sString )
end

function PrintLeft( nHeight, sString )
  term.setCursorPos( 1, nHeight )
  term.write( sString )
end

function PrintRight( nHeight, sString )
  term.setCursorPos( ( nScreenWidth + 1 ) - #sString, nHeight )
  term.write( sString )
end

function PrintTitle( sName )
  PrintCentered( 1, string.rep( "-", ( nScreenWidth + 1 ) ) )
  PrintCentered( 2, string.rep( "-", ( nScreenWidth + 1 ) ) )
  PrintLeft( 3, "-" )
  PrintCentered( 3, sName )
  PrintRight( 3, "-" )
  PrintCentered( 4, string.rep( "-", ( nScreenWidth + 1 ) ) )
  PrintCentered( 5, string.rep( "-", ( nScreenWidth + 1 ) ) )
  for i = 6, ( nScreenHeight - 1 ) do
	PrintLeft( i, "-" )
	PrintRight( i, "-" )
  PrintCentered( nScreenHeight, string.rep( "--", ( nScreenWidth + 1 ) ) )
  end
end

-- End Base Draw Functions

-- Menu Draw Functions --

function drawBoot()
  PrintTitle( "Boot Menu" )
  for j = 1, 3 do
	if j == nSelection then
	 PrintCentered( 11 + ( j - 1 ), "[" .. tMenus["Boot"].options[j] .. "]" )
	else
	 PrintCentered( 11 + ( j - 1 ), " " .. tMenus["Boot"].options[j] .. " " )
	end
  end
end

function drawInventory()
  PrintTitle( "Inventory Menu" )
  for k = 1, 2 do
	if k == nSelection then
	 PrintCentered( 11 + ( k - 1 ), "[" .. tMenus["Inventory"].options[k] .. "]" )
	else
	 PrintCentered( 11 + ( k - 1 ), " " .. tMenus["Inventory"].options[k] .. " " )
	end
  end
end

-- End Menu Draw Functions --

-- -- End Draw Functions -- --

while true do
  ClearScreen()

  -- -- Problem lies here -- --
  -- drawBoot() -- shows changing of selections
  tMenus[menustate].draw() -- doesn't show changing of selections

  local id, nKey = os.pullEvent("key")
	  if nKey == 200 and nSelection > 1 then
	nSelection = nSelection - 1
	  elseif nKey == 208 and nSelection < #tMenus[menustate].options then
	nSelection = nSelection + 1
	  elseif nKey == 28 then
	menustate = tMenus[menustate].options[nSelection]

	  end
  end