Make global [A][L][P] active w/o [Select all]

[phraenquex]

Turns out, it's disruptive to have to click [Select all] before having access to the [A/P/L] buttons in the observation view.

So

• keep those buttons active, and if nothing is selected, make them (a) select everything and (b) then turn everything on.
• if something is selected, turn on only the selected
• Update their tooltip: all interactions (if none selected, selects all)
• Change this in Navigation pane too (it's less annoying there, but better to keep behaviour consistent).

(If this is not a quick win, then stick it into the rethink of how to drive NGL displays from the LHS. Can't find the ticket, now, @mwinokan can you help?)