I have 2 forms in 1 MDI form, I want the 2nd form check the 1st form is it already open or not ..? how to do that ?? any body can help me please ?, by the way I have try the following codes:

in my module1.bas:

Declare Function FindWindow Lib "user32" Alias "FindWindowA" (ByVal lpClassName As String, ByVal lpWindowName As String) As Long

in my 2nd form:

Dim winHwnd As Long
Dim RetVal As Long
is_it_open = FindWindow(vbNullString, "Calculator")
Debug.Print winHwnd
If is_it_run = 0 Then
MsgBox "The form is not open"
End If

the above codes is running well, if I set False for MDIChild for the 1st form.

thanks for any advice or suggestion

Winan