Tkinter (Python): How to treat a modified click as just a click

Question

When Tkinter detects a modified click event such as <Shift-Button-1>, <Control-Button-1>, etc. is there a way to "stub out" the modifier key and have it handled as merely <Button-1> instead?

The only approach I can think of -- which isn't working for my use case -- is to create event bindings for the various modifiers, and then point them all to a callback that triggers the unmodified event. E.g.,

import Tkinter as tk
root = tk.Tk()
lst = tk.Listbox(root,selectmode=tk.EXTENDED)
[...geometry setup...]

def clickOnly(*args):
    lst.event_generate('<Button-1>')

lst.bind('<Shift-Button-1>',clickOnly)
lst.bind('<Control-Button-1>',clickOnly)
[...other related bindings...]

tk.mainloop()

When I run this code, the shift-click etc. are intercepted by the callback but the behavioral results deviate from what the plain click would do. E.g. the shift-click gets anchored to the item at index 0 and still selects multiple items instead of just the clicked one.

Guidance on how to correct my approach would be fine, but I'm really hoping someone can point me to a different, cleaner approach -- some more direct way to have the shift, control, and other modifiers treated as if they were always false.

(Environment is Python 2.7.x, running on Windows 7/10.)

EDIT: What I'm trying to make happen is this:

1. User points and clicks: Default behavior
2. User points and shift-clicks: Shift ignored, default behavior for a click
3. User points and control-clicks: Control ignored, default behavior for a click
4. User points and alt-clicks: Alt ignored, default behavior for a click
5. (you get the idea)

I.e. there any way to make Tkinter ignore the modifiers?

Answer 1

The simplest solution is to create explicit bindings to do exactly what you want, and then to prevent the default binding from occurring. You can do the latter by having your bound function return the string "break".

Example:

import Tkinter as tk
root = tk.Tk()
lst = tk.Listbox(root,selectmode=tk.EXTENDED)
lst.pack()
lst.insert("end", "one", "two", "three", "four", "five")

def clickOnly(event):
    index = '@%s,%s' % (event.x, event.y)
    event.widget.focus_set()
    event.widget.select_clear(0, "end")
    event.widget.select_set(index)
    event.widget.activate(index)
    event.widget.select_anchor(index)
    return "break"

lst.bind('<Any-ButtonPress-1>', clickOnly)

tk.mainloop()