Tkinter ttk Treeview binding responds to past events!

[John O'Hagan]

I was surprised that the code below prints 'called' three times.


from tkinter import *
from tkinter.ttk import *

root=Tk()

def callback(*e):
    print('called')

tree = Treeview(root)
tree.pack()

iid = tree.insert('', 0, text='test')

tree.selection_set(iid)
tree.selection_remove(iid)
tree.selection_set(iid)

tree.bind('<<TreeviewSelect>>', callback)

mainloop()

In other words, selection events that occurred _before_ the callback
function was bound to the Treeview selections are triggering the
function upon binding. AFAIK, no other tk widget/binding combination
behaves this way (although I haven't tried all of them).

This was a problem because I wanted to reset the contents of the
Treeview without triggering a relatively expensive bound function, but
found that temporarily unbinding didn't prevent the calls.

I've worked around this by using a regular button-click binding for
selection instead, but I'm curious if anyone can cast any light on
this.

Cheers

John