[Gambas-user] How to close a modal dialog form?

[M. Cs.]

Since the language of help documents aren't as clear to me, and I saw no
practical example I need your help. I would like to have a template message
dialog with title, text and an image I wrote a subroutine which would do the
things. It has an OK button upon itself, but I cannot close the window. I
would like this window to block other forms. How could I do that

PUBLIC SUB Messenger(naslov AS String, tekst AS String, slika AS String)
DIM imge AS PictureBox
DIM conti AS TextLabel
DIM butty AS Button
keret = NEW Form
keret.Width = 500
keret.Height = 300
keret.Title = naslov
imge = NEW PictureBox(keret)
imge.x = 0
imge.y = 0
imge.Width = 280
imge.Height = 280
imge.Border = TRUE
imge.Picture = Picture[slika]
conti = NEW TextLabel(keret)
conti.x = 300
conti.y = 20
conti.Width = 190
conti.Height = 230
conti.Text = tekst
butty = NEW Button(keret)
butty.x = 340
butty.y = 250
butty.Width = 120
butty.Height = 25
butty.Text = MessageYes.Text
keret.Center
keret.ShowModal()
Object.Attach(butty, ME, "Ops")
Message("Hm")
END

PUBLIC SUB Ops_Click() AS Integer
keret.Close()
END