Minipanels are a great way to group pane content. A big limitation for sitebuilders is that in the UI a minipanel is a blackbox the content of which is configured on a completely separate screen.
UI-wise minipanels behave like panel regions. Especially drag-and-drop of panes in and out of minipanels is possible.
* When editing a content type panel, minipanels can be used as flexibly as fieldgroups in node display/form settings.
User interface changes
See "Proposed resolution".