WoWInterface - SetScale bug with frames

When Setting the scale. Its size is reduced.

Expected result is framesize shouldn't change, but visual size should be 5x larger

UPDATE: Did some more testing. If you setscale to MyBaseFrame it works fine. So there's a bug or something with setpoints and scale
Tested this on the PTR today, and still bugs out

Code:

local FrameBorder = {

  bgFile  = '',

  edgeFile = [[Interface\DialogFrame\UI-DialogBox-Border]],

  tile = true,

  tileSize = 16,

  edgeSize = 6,

  insets = {

      left = -4 ,

      right = -4,

      top = -4,

      bottom = -4

  }

}



if MyBaseFrame == nil then

  MyBaseFrame = CreateFrame('Frame', nil, UIParent)

  MyBaseFrame:SetSize(100, 100)

  MyBaseFrame:SetPoint('LEFT', 100, 0)

end



if MyScaleFrame == nil then

  MyScaleFrame = CreateFrame('Frame', nil, MyBaseFrame)

  MyScaleFrame:SetAllPoints()

end



if MyFrame == nil then

  MyFrame = CreateFrame('Frame', nil, MyScaleFrame)

  MyFrame:SetAllPoints()

  MyFrame:SetBackdrop(FrameBorder)

end



local MB = MyBaseFrame

local SF = MyScaleFrame

local MF = MyFrame





SF:SetScale(5)



C_Timer.After(1, function() print(MF:GetSize()) end)