(Resolved) Check if form is loaded before starting another instance

[FastEddie]

I have a Parent form that loads a child form and I only want to allow one instance of the child form. I have this on the button to open the form. Stepping through the code with the debugger it "appears" to work OK when the form is open (I say appears because nothing changes) but when the form is closed it doesn't open as I would expect. What am I missing?

'
        Dim aForm As New frmCSA
        If aForm Is Nothing Then
            aForm.MdiParent = Me
            aForm.Show()
        Else
            aForm.BringToFront()
        End If