Version: (using KDE KDE 3.5.5) Installed from: Debian testing/unstable Packages Applications like GIMP or QTDesigner have a multi-window environment. When you launch one of this application in KDE if you switch to another application (like a browser) and then switch back to GIMP for example you have to bring up each window manually. In OSX this is handled by the window manager, when you click on a windows of that application, *all* of the windows are bring to foreground.
*** Bug 138185 has been marked as a duplicate of this bug. ***
FYI, I implemented this behavior in Blackbox a while back. I would recommend trying it to get an idea of how the feature could work.
I've been thinking about this and had some ideas about implementation which I've posted to blogspot: http://maninalift.blogspot.com/2008/06/kwin-window-groups.html It's probably bad form to link to a blog :( sorry. I'd love to hear about how the blackbox implementation works, it doesn't seem to be listed in the features of fluxbox unless by "grouped" you mean tabbed.
I'm sorry that no developer has replied to this feature request for such a long time. The root problem highlighted in this feature request is the rather bad handling of GIMP windows. This is unfotunately a problem of this specific application and in general we do not implement workarounds for one application. Hardly any other application has a multi-window approach similar to GIMP. Currently the GIMP developers are working on finally fixing this with a single window mode (see http://www.gimp.org/release-notes/gimp-2.7.html). Which obsoletes the need for more specific changes in the window managers. Additionally KWin gained JavaScript bindings for the next version. One of the example scripts I have written so far is to place all GIMP windows on a new desktop when a gimp window is opened. This script will be distributed in some way with the 4.9 release.