Google Earth User Guide - Manual (Page 122)

Select Spacebar Spacebar Toggles the check
mark of the
highlighted item on
or off, showing or
hiding display of
the item in the 3D
viewer.
Next Down arrow Down arrow Selects the next
item in the list
(either folder or
placemark).
Previous Up arrow Up arrow Selects the
previous item in the
list (either folder or
placemark).
Open Folder Right arrow Right arrow If the item selected
is a folder, opens
the folder to display
contents.
Close Folder Left arrow Left arrow If the item selected
is a folder, closes it
to hide contents
from the list view.
Delete Delete Key Delete Key Works only for
items in Places
panel. Deletes item
after confirmation
dialog box is
accepted.
Change overlay
opacity Scroll wheel Scroll wheel After you click the
slider, this changes
the transparency
for an overlay
selected in the
Places panel when
the mouse pointer
is positioned on the
overlay opacity
slider. Scroll
DOWN to make the
overlay image
more opaque,
scroll UP to make
the overlay more
transparent.