Move layers from a window to another.
Object
Windows can be linked only to 
Layer objects.
Gamgi expects users to identify first a window or list of windows
and then a layer. When the 
Window entry is active 
and empty, pressing the mouse over the graphic area in the current
window (local selection) creates a menu with all the windows in Gamgi, 
which can then be selected. Initially, the identification of the current 
window is entered in the 
Window entry.
Gamgi is now expecting users to click over the graphic area in a 
window (global selection), to create a menu with all the layers in 
that window, which can then be selected, to enter the 
Layer 
entry.
In the link mode 
Object, the selected layer must be in a different 
window. In the link mode 
All, the layer can be any layer in the 
selected window or any non-empty layer in another window.
Link
Gamgi suppports two linking modes for windows: 
Object and 
All.
The 
Object method links a window to a single 
Layer.
The layer is unlinked from its previous window and linked to the 
new window. The layer history kept by the 
Undo and 
Save 
mechanisms is preserved in this operation. An error is issued when 
the selected layer was already in the window.
After the linking operation, Gamgi always 
puts on top the selected window and layer.
The 
All method moves all the non-empty layers in all the
other windows to the selected window, remove all the other windows
which now have only empty layers, and finally put the selected
layer as current layer. An error is issued when the selected layer 
cannot be found among the layers reunited in the window.