Hi @tobl and thanks for your query. You will be pleased to know that we have produced a number of samples illustrating how to implement gaze aware controls effectively within WPF forms which you can download freely @ https://github.com/Tobii/interaction-samples
If you check out the ‘WPFSamples’ , this should hopefully illustrate for you the correct methodology for getting your project up and running!
Please try and do let us know if we can be of any further assistance. Best Wishes.
If may also interest you to know that we have a newer Interaction API currently in Beta @ https://developer.tobii.com/consumer-eye-trackers-interaction-library/
which has a more lightweight and simpler interface.