SHELL is the main container object. It's the only one that can start
an object hierarchy. It owns a window which displays all its descendent
objects. The SHELL' child arrangement policy is the same as the RowForm,
so, each child you add to the SHELL is placed above the previous.
Of course, if you need to have a different arrangement, you can add
a Form object performing the desired arrangement as direct child of the
SHELL, and then create other objects as children of the Form.
The 'Object Specific' dialog window allows you to modify the
default child spacing, the SHELL Type, the 'On Close' action
and the 'Option buttons'.
A popup SHELL appears with no title bar. It's primarily used
to popup menus.
By default a SHELL and all its descendents (all objects in the window)
are destroyed when the user clicks on the close button of the window. By
choosing 'Unrealize' you'll get the window removed from the screen
when the user chooses to close the window. All objects in that window are
however still valid and such 'unrealized' SHELL can be realized again later.
Options in the 'Option buttons' column establish the control
buttons to enable in the window's title bar.