There's a tinyish problem ...
The expression does nothing. AngelScript recognizes it as valid and all, but the inactive stays inactive.
I even made sure a specific item first and then all items do not deactivate, but nothing. It doesn't affect anything.
Then I tried to replace xTile and yTile with their actual values. Still nothing.
It didn't work as a stand alone, so I tried to inject it in onMain(), but it said "Expected ; Instead found @"
Then I tried to remove the upper path, the one who returns null, and only kept the other. Guess what? Nothing!
In the end, I tried to add the "else" line between the two paths. And still nothing!

Maybe I should get back to tileset making ...
I said MAYBE