Public Class Form1

    Implements IMessageFilter

    Public Function PreFilterMessage(ByRef m As Message) As Boolean Implements IMessageFilter.PreFilterMessage

        Const WM_RBUTTONDOWN  As Integer = &H204

        Const WM_RBUTTONDBLCLK As Integer = &H206

        ' check that the message is WM_RBUTTONDOWN Or WM_RBUTTONDBLCLK

        ' verify AxWebBrowser1 is not null

        ' verify the target is AxWebBrowser1

        Return (m.Msg = WM_RBUTTONDOWN OrElse m.Msg = WM_RBUTTONDBLCLK) AndAlso (AxWebBrowser1 IsNot Nothing) AndAlso (AxWebBrowser1 Is Control.FromChildHandle(m.HWnd))

    End Function

    Protected Overrides Sub OnActivated(e As EventArgs)

        MyBase.OnActivated(e)

        ' Filter is application wide, activate filter with form

        Application.AddMessageFilter(Me)

    End Sub

    Protected Overrides Sub OnDeactivate(e As EventArgs)

        MyBase.OnDeactivate(e)

        ' Filter is application wide, remove when form not active

        Application.RemoveMessageFilter(Me)

    End Sub

End Class