Hi,

>
If there is another window on top then your drawing is clipped to the window context not to anything else. You only draw to the context/surface associated with the window.
>

Sorry. You're right. Unless, of course, you clear the WS_CLIPCHILDEN flag:

   Protected Overrides ReadOnly Property CreateParams() As CreateParams
        Get
            Dim CParams As CreateParams = MyBase.CreateParams
            CParams.Style = CParams.Style And Not WS_CLIPCHILDREN
            Return CParams
        End Get
    End Property

but that's just nit-picking<s>
Regards,
Viv