The purpose of winico is to allow a user to manage the icon on the tk toplevel and taskbar - http://sourceforge.net/projects/tcllib/ more specifically, http://tktable.sourceforge.net/ . Browse the CVS repository to find it.
Winico sources are also available through ftp://ftp.scriptics.com/pub/tcl/nightly-cvs/ .
Winico is indispensable for many desired Windows-specific manipulations. Tom Wilkason describes how to work with an icon in the system tray in a posting to the comp.lang.tcl newsgroup [L1 ].
*Question:* How does one query whether an icon is still in the tray or not?