There are alot of issues with the usuability of the old custom observer dialog so an new one is being designed and implemented. this is a tracker bug for that.
*** Bug 2368 has been marked as a duplicate of this bug. ***
Progress: The following is now supported: - Show Current Observers - Create new Observers - Edit current Observers. - add Filters - remove filters - see added filters This shows filter combo's instead of fitlers and FilterPoints see (http://sourceware.org/bugzilla/show_bug.cgi?id=2460)
Progress: - You can now add new filters to an observer - set the argument of that filter - show arguments already set
Progress: - Edit actions - add actions - remove acitons - edit added actions - pass arguments to actions (auto completion is available where it makes sence)
this task is finished. Only fixing bugs that are uncovered is left
changing it to a tracker