Hi Yagoub,
Sorry for the late reply. Unfortunately the link to your project doesn’t work any longer, but I have in the recent days discovered a bug in the SDK which I suspect causes the behavior you describe. In short, the gaze aware behavior is dropped when a user control is hidden then shown again. We have a fix for it and it will be included in the next SDK release.
The only workaround I have found is to create a new UserControl object each time you want to display it.
Best regards,
Eddie