Don't send batch interactive to the combobox, you just put the environment into batch interactive when you run your script.
Names default to here(1);
new window("Example",
combobox({"Thing 1", "Thing 2", "Thing 3"},
<<Set Function(
Function({self, value},
print(value);
if( value == 2,
throw("This should throw a popup")
, //elif
value == 3,
batch Interactive(1);
throw("This should throw to log");
batch Interactive(0);
)
)
)
)
)