Plane->Select selects an plane or a list of planes.
To select an plane click the mouse over its visual representation:
if GAMGI recognizes the plane it becomes the new selected
object, otherwise the mouse action is ignored.
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 planes in the working layer can be selected, even if
planes are visible in other (transparent or translucid) layers.
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.
Plane->Select shows a flat list of all planes currently
existent in GAMGI, not necessarily in the same layer or window.
For each plane, a hierarchical tree shows all its child objects.