HAS to be inside a form and works best if in the same form of the field you are changing.
Otherwise it may not be shown or won’t be able to do searches.
HAS to refresh the ENCLOSING box the field is in, not the field itself; can be a PropertyLine.
Otherwise it won’t work in IE. Works without this trick in FF or GC.
Apparently you have to do the same with the Refresh family of Output controls.