Private Sub Form_Resize()
   On Error Resume Next
   rtfText.Move 100, 100, ScaleWidth - 200, ScaleHeight - 200
   rtfText.RightMargin = rtfText.Width - 400
End Sub

rtfText.RightMargin = rtfText.Width - 400 什么意思呢

rtftext右邊距的寬度等于rtftext的寬度減400