Numlock autocasting trick

Hi,

I'm trying to figure out how to make numlock autocasting trick to work with isboxer.

Long story short: https://www.youtube.com/watch?v=JaAI8s8rft4

Bind key to NUMPADx in Diablo 3, hold it, press numlock and character will keep casting it. It works fine with isboxer until I have to switch to other character with active window swapping. It seems like it is resetting all pressed keys or something like that.

Is there a way to persist pressed keys or keep status?

Thanks.