Holy cow, I wrote a book!
One of the most obscure keyboard shortcuts has got to be Shift+F8,
which is used for listbox discontiguous extended selection.
Man, what a mouthful.
KB article Q301583 doesn't help matters by listing this
keyboard shortcut under "Dialog box keyboard shortcuts" even
though it isn't a dialog box keyboard shortcut.
It's a listbox keyboard shortcut.
If the listbox supports extended selections
then you can use the Shift+F8 shortcut to create discontiguous
multiple selections from the keyboard.
(Via the mouse, you can just Ctrl+Click to create a discontiguous
Type Shift+F8 once to enter extended selection mode,
then use the arrow keys to select an item
and press Ctrl+Space or Shift+Space to select (or deselect) it.
When finished, type Shift+F8 again (or just move focus to some
And yes, this particular keyboard interface is pretty wacked out.
A more natural mechanism would be to have Ctrl+Arrow move the
focus without changing the selection, then using Ctrl+Space to
select (or deselect) the focus item.
Thankfully, the list view control went for that approach rather
than emulating the crazy Shift+F8 keyboard shortcut.