I’d like to see resolution to this thread because I am seeing the same problem here. I basically did all the same things that Brian did and I’m getting the “invalid command name” error. I’m using the same default tcl code provided through the designer with a couple minor tweaks to the proc name, very basic, etc. and can’t get it to fire.
Additionally, it would be nice to know what exactly the Comparing: value is related to. I’ve tried 0 — I think that covers all bases — but the thing never fires. Of course, an invalid command name “my_test” could be preventing it, but it’s hard to say what is going on.