Hi Zahid,You may wish to go to Adobe - LiveCycle Developer Center | Adobe Developer Connection (adobe.com/devnet/livecycle.html).   In the lower right section of the page under Downloads and Updates, you will find a download for AEM Forms Designer and its serial number.  This version supercedes Live...

I've found that it is most helpful to start at the top of a form and work down, testing for correct functionality on expanding sub-elements before you add new elements lower down on the form page.My comments are based on you working within the "(untitled Subform) (page1)" or equivalent area portion ...

I've also struggled with this exact problem and offer the following solution that has taken many hours of research.  I'm using Acrobat Pro DC and LiveCycle ES4 (and also works with LC2):Within LC save the form in a repository locationOpen the saved form in Acrobat DC ProGo to File>Create Form within...