Hi @sarahhosni, certainly you can use the Tobii EyeX to click a button or textbox within a Windows Form using your eyes.. that indeed is the intention with the Interaction API within the Core SDK!
I am not sure if you are aware but we have created a series of samples to show developers how to use our Interaction API to build interactive eye tracking enabled games and applications. You can find these @ https://github.com/Tobii/interaction-samples
Here is included several methods of using eye gaze to click buttons (and other WPF components) which hopefully should guide
you in the right direction.
I can’t say I understand the issue you were describing with reference to the clicking in other position, if you can perhaps show a screenshot or video of this problem, that would be ideal.
In any event, please try these new samples and let us know if we can be of any further assistance.