OpenControl

[hh]

From your answer I understand now what's the point.

You have a (shared) backgroundGroup that should go on some or all cards and you wish to change some properties of the group or its members depending on the card you wish to go to.

Right? For this situation I use the following.

We have one (shared) background group G
1) Give the group a customProperty array f that has these properties as elements,
   say f[i] = the properties to set in group G before opening card i.
2) Place the group on EVERY card and add instead it's *visible property* to f[i].
3) Do all changes in a preOpenCard handler in the group's script.

For beginners who read this: Such a group is in the message path by default AFTER card and stack. The only condition is now, that this is message is not "trapped" (= writing a preopenstack handler there and not passing it before e.g. by card or stack). This works always for me and the group is "effectively" (in size) only once in the stack.
This is somehow close to Mark's proposition (preOpenCard as frontscript, see above), but one doesn't have to control the message path as this uses a *backscript* by default.

Please write us a short note here (or in the forum, past Craig's post, see Richmond's link above) if this has besides "trapping" some more limitations we don't know of.

Hermann