way to allow interactive placement without allowing the user to resize the window.
The Shell widget class defines the XmNallowShellResize resource that is inherited by all of its subclasses. This
resource specifies whether or not the shell allows itself to be resized when its widget children are resized, but it does
not affect whether the user can resize the window. For example, if the number of items in a List widget grows, the
widget tries to increase its own size, which causes a rippling effect that eventually reaches the top−level window. If
XmNallowShellResize is True for this shell, it grows, subject to the window manager's approval, of course.
However, if the resource is False, the shell does not even consult the window manager because it knows that it
doesn't want to resize. This resource only prevents the shell from resizing after it has been realized, so it does not
interfere with the initial sizing of the shell.
17.2.3 The Shell's Icon
Shells can be in one of three states: normal, iconic, or withdrawn. When a shell is in its normal state, the user can
interact with the user−interface elements in the expected way. If a shell is withdrawn, it is still active, but the user
cannot interact with it directly. When a shell is iconic, its window is not mapped to the screen, but instead it displays a
smaller image, or icon, that represents the entire window. The application is still running in this state, but the program
does not expect any user interaction. The icon window usually displays ...