Tk Toolkit

If a menu is created with multiple radiobutton entries, using "-indicatoron
1" on one of the entries has no effect. The value of the designated
variable overrides the option. If the designated variable is unset, the
flag still has no effect.

Example:

unset -nocomplain selectedButton
set m [menu .m -tearoff 0]
$m add radiobutton -label Accept -indicatoron 1
$m add radiobutton -label Reject
$m add radiobutton -label Undecided
tk_popup $m 0 0

The menu that appears has no menu entries selected.

Example 2:

destroy .m
set selectedButton Reject
set m [menu .m -tearoff 0]
$m add radiobutton -label Accept -indicatoron 1
$m add radiobutton -label Reject
$m add radiobutton -label Undecided
tk_popup $m 0 0

the menu that appears has "Reject" selected despite the use of the
-indicatoron flag.

Version 8.5.5 on Ubuntu Hardy.