Some things about backgrounds i never knew

David Bovill david at
Thu Dec 30 17:44:07 EST 2010

On 30 December 2010 21:24, J. Landman Gay <jacque at> wrote:

> You can place any group on a card, regardless of its backgroundBehavior.
> All of the background* functions return only those groups with
> backgroundBehavior set, whether or not the group is placed on the current
> card. It is unusual to assign a group backgroundBehavior and then turn it
> off again, but when you do that I believe the group's position in the
> message hierarchy will change and it will behave as a card group again.
> Because the group is placed on several cards, changes to it anywhere will
> reflect across all cards that contain the group. BackgroundBehavior doesn't
> affect whether changes populate across cards; if the ID matches, it's the
> same group.

Yes - that seems to be exactly right.

You don't need to worry about backgroundBehavior when checking groups for
> export. Just get "the number of groups" or "the groupnames of this card" and
> export them all. Those that are shared across other cards will still be in
> the list regardless of their backgroundBehavior setting.
> If instead you want to avoid exporting any background groups, then as you
> repeat through the list, check the group's backgroundBehavior and skip those
> where it's true.

Yes - those use cases are fine. I want to make sure I am not exporting
identical information about objects twice, so I want to know which groups in
a stack are  backgrounds in the shared id sense - there is no function for
this, so I've had to take a different approach and simply loop through every
card checking the ids.

I still really want to know what "background 2 of this stack" refers to -
any idea about that?

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