Now you tell me !!! 
I dont really see how it didnt put any load on the CPU but it doesnt. It does get called a lot because I tweak the function to keep a count every time it was called and moving the mouse made the count go up very quickly.
The majority of the load will be in bandwidth and CPU in the app itself. With a little refactoring, we could probably throttle them, but weāre not doing that now.
Having checked it I think it is fine as it is until such time as someone is tweak in the area and feels like enhancing it a little. I have logged it into feedback as <https://xojo.com/issue/34081>