Solved, thanks to other answer in this forum in this way:
Lua Code:
lpanels:CreateLayout("Back2", {
{ name = "P1", anchor_to = "BOTTOM", x_off = 0, y_off = 4,
bg_alpha = 1, width = 460, height = 122,
border = "SOLID", border_color = "CLASS",
},
{ name = "P2", parent = "BT4Bar10",
anchor_to="BOTTOMLEFT", anchor_from="BOTTOMRIGHT", anchor_frame = "P1",
x_off = 2, y_off = 0,
bg_alpha = 1, width = 115, height = 122,
border = "SOLID", border_color = "CLASS",
},
{ name = "P3", parent = "BT4Bar9",
anchor_to="BOTTOMRIGHT", anchor_from="BOTTOMLEFT", anchor_frame = "P1",
x_off = -2, y_off = 0,
bg_alpha = 1, width = 115, height = 122,
border = "SOLID", border_color = "CLASS",
},
} )
Without parenting with BT4 bars I think it is impossible.