Code:
frame.border = CreateFrame("Frame", nil, MyStatusBar)
frame.border:SetPoint("TOPLEFT", MyStatusBar, "TOPLEFT", -2, 2)
frame.border:SetPoint("BOTTOMRIGHT", MyStatusBar, "BOTTOMRIGHT", 2, -2)
frame.border:SetBackdrop({
bgFile = YOUR_TEXTURE,
edgeFile = YOUR_TEXTURE,
tile = false, tileSize = 0, edgeSize = 1,
insets = { left = -1, right = -1, top = -1, bottom = -1}
})
frame.border:SetFrameLevel(MyStatusBar:GetFrameLevel())