@Claude31 Thanks for you reply. I set ScrollView>ClipView to not draw background by design.
Because I want to show some changing text in the window and at the same time I can see text below the window. so I want to have a textview with transparent background (100% transparent)
" how do you set the full view to be transparent ? " I set NSWindow backgroundColor = .clear and disable ScrollView, ClipView to draw background.