Gui script help?

it's a Gui to get items from a backpack, it works but it doesnt go down the Y scale with a new item does anybody know how to make it do that? -- Image: http://tinypic.com/r/2ilggow/9

-- Script below

function GenerateCell(X,Y) local Cell = Instance.new("TextButton") Cell.BackgroundColor3 = Color3.new(0,0,0) Cell.BorderColor3 = Color3.new(1,1,1) Cell.TextColor3 = Color3.new(1,1,1) Cell.BackgroundTransparency = 0.4 Cell.Name = "Cell" Cell.Font = "ArialBold" Cell.FontSize = "Size12" Cell.Text = "" Cell.Visible = false Cell.Active = true Cell.Position = UDim2.new((X-1)(1/Div),1,(Y-1)(1/Div),1) Cell.Size = UDim2.new(4/Div,10,1/Div,-2)