Version: (using KDE 4.1.2) OS: Linux Installed from: Ubuntu Packages If you close the application window and then click on the system tray icon, it is shown again (which is how it should be). If you however minimize the window and then close it, a click on the system tray icon does not restore the window, but only shows the printer applet in the taskbar, so you have to click on the taskbar entry to raise the window. Usually the user wants to see the printer applet when clicking the system tray icon, so there is no reason why it should open minimized, even it has been minimized before closing.
Now using v1.5 of the applet in kde 4.5.1 this issue is fixed.