In a different forum a user reminded me of a speed tip that had cropped up once or twice over the years. It has to do with popupmenus.
Basically on older versions of macOS if you did
PopupMenu1.ListIndex = -1
For i As Integer = 0 To 1000
PopupMenu1.AddRow Str(i)
Next
This behaved not so badly although there is a slightly faster variation
But on Mojave this is noticeably slow.… Read the rest