http://purl.org/tcl/home/man/tcl8.4/TkCmd/optionMenu.htm
Note: Unlike most Tk widgets, this widget's name (optionMenu) is not the same as its creation command (tk_optionMenu).
incr Widgets also has an optionMenu . Once their DNS problems are resolved, I will be adding URLs to their doc here.
Tk syntax help - Arts and crafts of Tcl-Tk programming - Category Command, part of the Tk and incr Widgets packages.