Link atoms to other objects.
Hierarchy
Atoms can be linked to objects above or below, in the Gamgi hierarchy. 
Pressing the button 
Below (the default), the 
Objects menu 
shows the classes of objects that can be owned by atoms: Orbital and Text 
(the default). Pressing the button 
Above, the same menu shows the 
classes of objects that can own atoms: Layer (the default), Assembly, Cell, 
Cluster, Molecule, Group, Plane and Direction.
Object
Gamgi expects users to identify first the atom or list of atoms
and then the object to link. When the 
Atom entry is active 
and empty, clicking the mouse over an atom, on the current layer
(local selection), its identification is transported to the 
Atom 
entry. Gamgi is now expecting users to click on a object of the class 
currently selected in the 
Object menu. This object can be in 
a different layer or even in a different window (global selection). 
To select a visible object in a different layer, in the same window, 
just press the mouse over the object, as if it was in the current 
layer. To select objects without visual representation, as layers
and lights, press the mouse over the graphic area in the window,
to create a menu with all the objects of that class in the window, 
which can then be selected. To select an object in a different window, 
with the mouse, use exactly the same procedure, in that window.
Link
Gamgi suppports only one type of linking mode for Cluster: 
Object.
The 
Object method links an atom to a single 
Object. 
When the 
Hierarchy is 
Above, the atom is unlinked from 
its current parent and linked to the object. When the atom is
moved to a different layer, all its bonds are autmatically removed.
When the 
Hierarchy is 
Below, the object is unlinked
from its current parent and linked to the atom. An error is
issued when the parent already owned the child object.
After the linking operation, Gamgi always puts on top
the window and layer containing the linked objects.