[gmarco]

I am doing good progress

The code finally is displaying something :-)

local NUM_BUTTONS = 8
local BUTTON_HEIGHT = 20
local BUTTON_WIDTH = 96
 
local list = {"aaaa","bbbbb","cccccc","ddddddd","eeeeee","ffffff","gggggg","hhhhh"}
local buttons = {}
 
local function update(self)
    local numItems = #list
    print ("DEBUG: nr. items " .. numItems)
    FauxScrollFrame_Update(self, numItems, NUM_BUTTONS, BUTTON_HEIGHT)
    local offset = FauxScrollFrame_GetOffset(self)
    for line = 1, NUM_BUTTONS do
        local lineplusoffset = line + offset
        local button = buttons[line]
        if lineplusoffset > numItems then
            button:Hide()
        else
            button:SetText(list[lineplusoffset])
            button:Show()
        end
    end
end
 
local scrollFrame = CreateFrame("ScrollFrame", "MyFirstNotReallyScrollFrame", UIParent, "FauxScrollFrameTemplate")
scrollFrame:SetWidth(BUTTON_WIDTH)
scrollFrame:SetHeight(BUTTON_HEIGHT*6)
scrollFrame:SetPoint("CENTER",UIParent)
scrollFrame:EnableMouse(true)
scrollFrame:SetMovable(true)
scrollFrame:RegisterForDrag("LeftButton")
scrollFrame:SetScript("OnDragStart", function(self) self:StartMoving() end)
scrollFrame:SetScript("OnDragStop", function(self) self:StopMovingOrSizing() end)
scrollFrame:Show()
scrollFrame:SetClampedToScreen(true)
scrollFrame:SetScript("OnVerticalScroll", function(self, offset)
    FauxScrollFrame_OnVerticalScroll(self, offset, BUTTON_HEIGHT, update)
end)
 
for i = 1, NUM_BUTTONS do
    local button = CreateFrame("Button", nil, scrollFrame:GetParent())
    if i == 1 then
        button:SetPoint("TOP", scrollFrame)
    else
        button:SetPoint("TOP", buttons[i - 1], "BOTTOM")
    end
    button:SetNormalFontObject("GameFontNormal")
    button:SetSize(BUTTON_WIDTH, BUTTON_HEIGHT)
    button:SetText(list[i])
    buttons[i] = button
end
 
 
 
-- enabling the last line will make the slidebar disappears.
-- print ("DEBUG: Force updating")
-- update(scrollFrame)

Now I get the scrollframe with sliders but it is wrong. You can check the picture to see...
It doesn't cover the out of scrollframe part nor it scrolls using the slide.

Other thing: If I enable the manual update of the frame (last line) the sliders will disappears (!??!) :-)

Thanks again for any inputs/clues/tips :-)