vb.net mdi child title bar not hiding

I have an issue hiding the title bar of a mdi child form in maximized state within a mdi parent form in .NET. Here's what I have at design & run time: Here is the new() of my MDI child form: ``` Public Sub New(ByRef pParent As Form) MyBase.New() Me.MdiParent = pParent fParent = pParent Me.Text = "" Me.FormBorderStyle = Windows.Forms.FormBorderStyle.None Me.WindowState = FormWindowState.Normal Me.MinimizeBox = False Me.MaximizeBox = False Me.ControlBox = False Me.ShowIcon = False Me.ShowInTaskbar = False Me.SizeGripStyle = Windows.Forms.SizeGripStyle.Hide Me.Dock = DockStyle.Fill End Sub ``` I've tried `FormWindowState.Maximized` and `DockStyle.None` instead but the result was the same. On the parent container, to change from a child to another I use this function: ``` Protected Sub SetActiveScreen(ByVal pChildForm As tWizardForm) If pChildForm Is Nothing Then Exit Sub If fActiveScreen Is pChildForm Then Exit Sub Dim hg As New tHourglass Try fActiveScreen = pChildForm fActiveScreen.Show() fActiveScreen.BringToFront() For Each aForm In MdiChildren If aForm IsNot fActiveScreen Then aForm.Hide() Next fActiveScreen.Execute() UpdateCaption() Finally hg.Dispose() End Try End Sub ``` At design I've set the parent property `IsMdiContainer = True`. Where did I go wrong or what have I missed ? Plus this kind of double buttons on the child title bar is really strange. When I click one of the maximize buttons I end up with the same result: . The resulting title bar buttons cannot be clicked. Thank you for any help !