Please refer code sample demos/editing/dialog-layout.php.
It allows you to have 2,3,4 column form.

Hi, this is only in the Full Version? It's posible to do with the free version?

Thanks

Yes, it is fully supported in full version. I think you can also check the behavior in free too.

// to place a column on first row, and first column
$col["formoptions"] = array("rowpos"=>"1", "colpos"=>"1");

// to place a column on first row, and second column
$col["formoptions"] = array("rowpos"=>"1", "colpos"=>"2");