invalid command name "toplevel"
    while executing
"toplevel .a"
    (in namespace eval "::request" script line 1)
    invoked from within
"namespace eval ::request $script"
    ("::try" body line 12)
OUTPUT BUFFER:
toplevel .a
button .a.b -text "here is .a.b\net hop" -bg green
pack .a.b

toplevel .b
button .b.b -text "hre is .b.b\n et re-hop" -bg red
pack .b.b

toplevel .c
button .c.b -text "hre is .c.b\n et fini les hop" -bg cyan
pack .c.b

proc ToggleW {key} {

    puts "Press $key"

    set Lt [wm stackorder .]
    set Ht [lindex $Lt end]
    if {$Ht eq "."} {set Ht [lindex $Lt end-1]}
    set Bs [lindex $Lt 0]
    if {$Bs eq "."} {set Bs [lindex $Lt 1]}

    lower $Ht
    raise $Bs
    focus $Bs

    return
}

#bind .      [list ToggleW %K]
#bind .a     [list ToggleW %K]
#bind .b     [list ToggleW %K]
#bind .c     [list ToggleW %K]
bind all  {puts "key= %K"}
bind all  [list ToggleW "%K"]
bind all  [list ToggleW "%K"]