Thanks for your response but MDI forms do not have the BorderStyle Property. I did however find a way to do it using the SetWindowLong Windows API Function
For future reference it goes like this:
Private Declare Function SetWindowLong Lib "user32" Alias "SetWindowLongA" (ByVal hwnd As Long, ByVal nIndex As Long, ByVal dwNewLong As Long) As Long
Private Const GWL_STYLE = -16
Private Const WS_NOSIZEMINIMIZE = 113901568
Private Sub MDIForm1_Load()
SetWindowLong Me.hwnd, GWL_STYLE, WS_NOSIZEMINIMIZE
End Sub
Note: Then WS_NOSIZEMINIMIZE is not an atual windows API constant. I created it. None of the constatns that I found did what I wanted to do. So I set up a normal form the way that I wanted the MDI form to work and used the GetWindowLong function and that returned me the number 113901568, which makes the MDI form operate in the same way as my test form.
Tnx again.