Need help with ingredients mod

[Tyx]

Hello everyone.
I am a total lua beginner but want to create a addon to see the level/tier of ingredients.
Because I am a noob in it I stole pretty much everything in my code from various genius modders
But now I am stuck.
I try to do the same as ingeniousclown with his brilliant research assistant but instead of showing a texture in the column I want to show the user a label with the tier of the item.
(The Version with a texture works more or less (of course my database is far from complete))

local function CreateTierControl(parent)
    local control = WINDOW_MANAGER:CreateControl(parent:GetName() .. "Tier", parent, CT_Label) -- if this is set to CT_Texture with more or less the same values it will show the texture and will be colorizable
    control:SetDimensions(30, 30)
    control:SetAnchor(CENTER, parent, CENTER, 100)
    control:SetText("Error")
    control:SetFont("ZoGameFont")
    control:SetHidden(true) -- even if this is set to false it will not show anything
    
    return control
end
 
local function AddTierToSlot(control)
    local bagId = control.dataEntry.data.bagId
    local slotIndex = control.dataEntry.data.slotIndex
    
    local tierControl = control:GetNamedChild("Tier")
    if(not tierControl) then
        tierControl = CreateTierControl(control)
        table.insert(controlsToWatch, tierControl)
    end
 
    local itemType = GetItemType(bagId, slotIndex)
    tierControl:SetHidden(true)
    if(itemType == ITEMTYPE_INGREDIENT) then
        local itemName = GetItemName(bagId, slotIndex)
        itemName = string.gsub(itemName,"s^p","") -- because of the annoying plural names
        local tier = getTier(language, itemName) -- will give back a number
        local color = getColor(language, itemName) -- will give back a color (black if item is not yet listed)
        if(tier ~= nil) then
            if(color == "green") then
                tierControl:SetColor(0, 1, 0, 1)
            elseif(color == "blue") then
                tierControl:SetColor(0, 0, 1, 1)
            elseif(color == "violet") then
                tierControl:SetColor(1, 0, 1, 1)
            elseif(color == "gold") then
                tierControl:SetColor(1, 1, 0, 1)
            else
                tierControl:SetColor(0, 0, 0, 0)
            end         
            tierControl:SetHidden(false)    
        end
    end
end

Like I said this is a bit stolen so it is for my personal use only until I have permission from ingeniousclown to edit his code and upload it. - But that will come later first I need to understand what I am doing wrong.

Sorry for my english I hope you can help me