Can NSIS stop/start an aplication? // Past Systray icons
Okay, I found this out a while ago.
When a portable application such as Pidgin or Miranda runs, windows will store the settings for the behavior of the system tray icon [Always Show, Always Hide, Hide when Inactive] in the registry. However, when the program closes, these settings are kept and will be displayed under "Past Items" in the customize notifications part of the Taskbar & Start Menu Properties. This exposes all the applications which use system tray icons, that have previously been running on the computer.
*gasps*