I'm not sure if this will be right everywhere, but it's perfectly centered for
me and corresponds to the spacing/padding that's present, so it seems right.
/* move the au_view down so that it doesn't overlap the top_box contents */
- NSPoint origin = { 0, static_cast<CGFloat> (a.height) };
+ const int spacing = 6; // main vbox spacing
+ const int pad = 4; // box pad
+
+ NSPoint origin = { spacing + pad, static_cast<CGFloat> (a.height) + (2 * spacing) + pad };
[au_view setFrameOrigin:origin];
[view addSubview:au_view positioned:NSWindowBelow relativeTo:NULL];