This is NOT a request for killing applications.
I can well kill all process, no matter what. That's not the issue.
The issue is:
When we "close" Skype or Banshee, or Korganizer or many many others, it is common that, after we do that, **we have an icon on the panel (near the clock).
However, that has not been the case here.
Once I do that, I have no icon on the panel, near the clock, as a result, I can't easily re-display the application window as normally should happen.
How can make those icons appear on the panel ?