How do I group/un-group parent/child windows?

I was rummaging around in gconf-editor yesterday, and I noticed a setting to Group or Un-group a set of windows... (but I forget the exact Key-name)

This setting was something which looked like a swtich to the default behavioural difference between Ubuntu and Windows... It was called something like: Group windows/dialogs

I switched to "Group". This locks a child window/dialog to the parent, so that it appears "on-top" of the parent (which is pretty much the MS-Windws standard). I thought I'd try it out, to see which mode I preferred...

An typical example of the "Grouped" behaviour is: An Open-file dialog is forced to stay on top of its parent, until it is closed.

24 hours later, I've decided I prefer the default Ubuntu way... but I can't find that option again.

Does anyone know which/where it is?

Solution 1:

The only known location for that sort of option is:

/apps/gnome/interface

Solution 2:

The answer to this question has been resolved in this askubuntu question ...

The transition from this question to the one I now refer you to, is explained in the comment I wrote to Martin's answer...