Thank you for the detailed answer. It was very helpful.
However, I did not suceed to track UI objects of another application.
Here is my situation: i have my own windows forms application where i initialize Tobii and everything related to it. It also has some UI, but I am not interested to track it. I am interested in UI of another application, which is a third-party windows application which source code i cannot access (but I can programmatically detect some UI elements of this application, their boundaries and so on).
What i did is that i took a windows form example from you examples set for .NET and slightly modified it for my needs. In two words, in my application I initialize Tobii and register an interactor that belongs to another application.
When I am debugging my code, i see that Tobii sends queries regarding interactors only if i am looking at the window of my application, even though i have no interactors registered in the boundaries of this window (only an interactor from the third-party application window). When I am looking outside my application window, Tobii does not even send the queries to my application(function HandleQuery which handles a query from the EyeX Engine is never called).
It seems that Tobii is in some way bounded to the initial application boundaries. Or am i doing something completely wrong ?