"Open packing list" switched to the Lists tab but left it on whichever
sub-tab was open last, so someone who had been in the to-dos landed there.
It now picks the packing side first, and a Lists tab already on screen
follows the choice; storage that is blocked no longer throws either.
With the Packing addon off, "Remove link" let go of the link on one click,
and the link cannot be made again until Packing is back on. It now opens
the tour's packing dialog with only the dimmed link and the Remove link and
Cancel buttons, so nothing changes without a second, deliberate click.
useListsSubTab remembers whether the packing or the to-do sub tab was
open, for ListsContainer and MTripShell. The desktop restores any stored
value, the phone restores todo and otherwise falls back to packing.
Maurice