Layer->Select selects a layer or a list of layers.
To select a layer click the mouse anywhere over the screen:
a menu pops up listing the identification of all the layers.
If a layer is selected, it becomes the new selected object.
When an object is selected, a beep is emitted and the object 
identification is shown in the window status bar, first in a       
highlighted color (to emphasize that the current object has 
changed) and then in the default color (after a few seconds).
Only layers in the current window can be selected. For each top 
window, only one selected object is maintained. This can be Gamgi 
(everything), Window (the current window), Layer (the current layer), 
or a child object of the current layer. To see which object is 
currently selected see its identification in the window statusbar.
When the selected object is a layer, this becomes also the selected
layer. To see which layer is currently selected see its identification 
in the window statusbar.
Layer->Select shows a flat list of all layers currently
existent in GAMGI, not necessarily in the same window. For each 
layer, a hierarchical tree shows all its child objects.