Hi @magnuslp, apologies for the delay in reply. So it sounds by the description of your project, that a global interactor is what you need.
Essentially, this is calling a gaze aware component to the entire windows form. Whilst did not produce documentation for this for the Core SDK, you can read the concept (which applies equally) for the EyeX SDK @ https://developer.tobii.com/c-sample-walk-minimalgazedatastream/
In addition, if you have not already, please download the Core SDK samples @ https://github.com/Tobii/CoreSDK
which show a similar methodology applied for console applications which you should be able to translate over to your WPF window.
Hopefully this points you in the right direction! Please do let us know if we can provide any further assistance.