Look here and here for the changelogs for ES3 and ES4http://help.adobe.com/en_US/livecycle/10.0/DesignerHelp/WS107c29ade9134a2c2439970312a9bd97a8f-8000.htmlAdobe LiveCycle ES4 * New features in Designer

I use separate machines to test on different versions.

See here LiveCycle Trial Download. It doesn't look like you can get a trial without contacting sales.

It'd love to be wrong, but I believe this feature is only available for HTML5 rendered forms, using the LiveCycle Server software.

Did anyone figure this out? I am trying to setFocus(null) from a mouseDown event, and it doesn't work! setFocus to another form object, does, however.

Please see this article for what options you have for deployment of your form:http://assuredynamics.com/index.php/2010/11/using-livecycle-forms-in-acrobat-and-reader/

If you put your fields in subforms, you can reference the subform instead of the fields and perform operations on them.

I've run into issues where Adobe Reader runs out of memory when using many images in a single PDF. I don't believe there is a limit to the number of images in the PDF format.

You may have some limited success getting static XFA forms to display on mobile devices. Dynamic XFA forms will only show the shell PDF (the one that says to upgrade your version of reader) in non XFA aware renderers.

I change the script to this and it worked:But you said you already tried that? So I'm wondering what version of Adobe Reader / Acrobat you are using to preview your form.