I used SetPoint() to cover my viewport with a texture, like this:
Code:
local toppanel = CreateFrame("Frame", nil, UIParent)
Code:
toppanel:SetPoint("TOPLEFT", -2, 0)
toppanel:SetPoint("TOPRIGHT", 2, 0)
toppanel:SetHeight(15)
or consequently
Code:
toppanel:SetPoint("TOPLEFT", -2, 0)
toppanel:SetPoint("TOPRIGHT", 2, -15)
Using a small offset for x just to make sure there's no clipping (aka a little visual gap). Not necessarily needed, I suppose.