Version: (using KDE 4.2.0) Installed from: Ubuntu Packages Some people don't use the quicklaunch applet because it uses precious space in the panel. Moreover many applications don't need to be launched twice. My idea is to automatically hide an icon of the applet when the corresponding application is displayed on the screen. The hidden icons could be accessible in the same way as the hidden icons of the systray applet. In windows 7, MS has merged the quicklaunch and the taskbar. It use less space because texts are not displayed. I don't think their choice is the best because it is less readable. My idea is a good compromise.
I don't think this is the purpose of the quicklaunch applet. If you need this functionality, you can use one of the "intelligent" task applets like stasks and others.