IN PROGRESS - issue CORE-4152: Implement App Integration WYSIWYG Pallete
Drag n' Drop 
https://pods.iplantcollaborative.org/jira/browse/CORE-4152

Selection of argument group content panel headers in the App Integration
window now open a bound Argument Group Editor.
Put null check into DefaultArgumentValueEditor
When new arguments or argument groups are dropped onto the wizard, their
properties panel will be shown. However, there is currently a bug where
this does not happen on the first argument dropped, but everything after
will have their properties shown. The same is true for argument groups.