By default, each window has four binding tags consisting of the name of the window, the window's class name, the name of the window's nearest toplevel ancestor, and all, in that order. Toplevel windows have only three tags by default, since the toplevel name is the same as that of the window. The bindtags command allows the binding tags for a window to be read and modified.
If bindtags is invoked with only one argument, then the current set of binding tags for window is returned as a list. If the tagList argument is specified to bindtags, then it must be a proper list; the tags for window are changed to the elements of the list. The elements of tagList may be arbitrary strings; however, any tag starting with a dot is treated as the name of a window; if no window by that name exists at the time an event is processed, then the tag is ignored for that event. The order of the elements in tagList determines the order in which binding scripts are executed in response to events. For example, the command
bindtags .b {all . Button .b}
reverses the order in which binding scripts will be evaluated for
a button named .b so that all bindings are invoked
first, following by bindings for .b's toplevel
(“.”),
followed by class bindings, followed by bindings for .b.
If tagList is an empty list then the binding tags for window
are returned to the default state described above.
The bindtags command may be used to introduce arbitrary additional binding tags for a window, or to remove standard tags. For example, the command
bindtags .b {.b TrickyButton . all}
replaces the Button tag for .b with TrickyButton.
This means that the default widget bindings for buttons, which are
associated with the Button tag, will no longer apply to .b,
but any bindings associated with TrickyButton (perhaps some
new button behavior) will apply.
proc setupBindtagsForTreeDelivery {widget} {
set tags [list $widget [winfo class $widget]]
set w $widget
set t [winfo toplevel $w]
while {$w ne $t} {
set w [winfo parent $w]
lappend tags $w
}
lappend tags all
bindtags $widget $tags
}