With the header “Borderless Window” there have been conversations. But - as far as I see - the solution was always a window with WindowStyle = “None” but with a border ( a Plain Box as frame).
In Windows WPF-Programming I can additionally set AllowsTransparency=“True” and have a real borderless window, only a rectangle with the backgoundcolor (like a canvas ).
Sub Open()
Declare Function SetWindowLongW Lib "User32" (HWND As Integer, Index As Integer, NewLong As Integer) As Integer
Const GWL_STYLE = -16
Const WS_POPUP = &h80000000
Call SetWindowLongW(Me.Handle, GWL_STYLE, WS_POPUP)
End Sub