[fatrog]

Hello,

Thank you so much for explainations. And sorry for very late answer.

So, as you suggested, I have made it like this:

local function GetItemGCDInfos(tt)
    ctt = TooltipUtil.GetDisplayedItem(tt)
    gcdMS, cooldownMS, spellID, ItemLink = nil
    
    if ctt ~= nil then
        _, ItemLink = ctt:GetItem()
        _, spellID = GetItemSpell(ItemLink)
    end
    
    if spellID ~= nil then
        cooldownMS, gcdMS = GetSpellBaseCooldown(spellID)
    end
    
    if gcdMS ~= nil then
        SetNewLineWithGCD(ctt,gcdMS)
    end
end

Unfortunatly, I still got the same error (eg. when I get multiple tooltip like when I put my cursor over the suggested items in the "edit stuff" menu)