Creating widget groups in Editor is useful when you want a set of widgets to maintain their relative size and position. You will also find many widget groups in most libraries.
To create a group
Select all the widgets you want to include in the group using [Ctrl] + [Click] (Win) or [Cmd] + [Click] (OSX). Alternatively, you can lasso all the widgets you want to include.
Right-click on one of the selected widgets and select 'Group' or use the keyboard shortcut [Ctrl] + [G] (Win) or [Cmd] + [G] (OSX).
That will create the group of widgets. Clicking on any member of a group will select the group. To 'open' the group and edit the member of the group, double click on any member of the group.
Right-click on the highlighted group and select 'Ungroup' or use the keyboard shortcut [Ctrl] + [Shift] + [G] (Win) or [Cmd] + [Shift] + [G] (OSX).