Track FX Visibliity control

Didn`t understood what target_track_id means (especially if you already have range), but a bit cleared lua code looks like this: Code:

Thanks - seems I have some more context 

Thanks for your input, I'll test that out. The reason for a target track is that I need to associate multiple instances of this script with separate tracks, the idea being to show only the instrument UI related to that track and shut down all others within the range. (I have nearly a dozen synths and the screen gets awfully cluttered, in this way when i send a program change to one instrument this script makes its UI the only visible one.) However the windows that don't respond seem to all be the same 3rd party vst, so maybe the issue is in the vst itself and perhaps in the memory space it occupies. Perhaps it loads into different memory space and cannot receive the close-window message. Thanks for your time!