Switching users in app

Hi All

is it possible (in a test app) to login as user 1, view files etc, then log out and log in as user 2, view their files etc?

My app is using an OAuth2 flow in .net, its a windows forms app.

during the authentication routine, it opens a browser window and presents the login page. the access token is then kept to validate operations.

when logging out, i remove the access token (set to string.empty), in addition - ive also sent a TokenRevokeAsync request. after awaiting that event it loads up the login browser and immediately restores the previous access token.

Im using the Developer API for .net (official) 

the method on the login form(browser) that is called, is:

        Public Sub Start(ByVal appKey As String)
            Me.oauth2State = Guid.NewGuid().ToString("N")
            Dim authorizeUri = DropboxOAuth2Helper.GetAuthorizeUri(OAuthResponseType.Token, appKey, New Uri(RedirectUri), oauth2State, False, False)
            Me.Browser.Navigate(authorizeUri)
        End Sub

then:

      Private Sub BrowserNavigating(ByVal sender As Object, ByVal e As NavigatingCancelEventArgs)
            If (Not e.Uri.ToString().StartsWith(RedirectUri, StringComparison.OrdinalIgnoreCase)) Then
                ' we need to ignore all navigation that isn't to the redirect uri.
                Return
            End If

            Try
                    Dim Result As OAuth2Response = DropboxOAuth2Helper.ParseTokenFragment(e.Uri)
                If (Result.State <> Me.oauth2State) Then
                    Return
                End If
                Me.AccessToken = Result.AccessToken
                    Me.Uid = Result.Uid
                    Me.Result = True
                Catch eww As ArgumentException
                    ' There was an error in the URI passed to ParseTokenFragment
                Finally
                    e.Cancel = True
                    newAttempt = False
                    Me.Browser.Navigate("about:blank") ' nav away
                    Me.Hide()
                End Try
        End Sub

Could anyone suggest anything to make this work?

BTW: on first run, there is no credential stored so i know this is something to do with cached credentials.