# tk_super_textbox_multiselect.py

# tk_super_textbox_multiselect.py

import tkinter as tk
from collections import deque

def do_toggle(i):
    if i in toggle:
        text.tag_remove("highlight", f"{i}.0", f"{i+1}.0")
        toggle.remove(i)
    else:
        text.tag_add("highlight", f"{i}.0", f"{i+1}.0")
        toggle.append(i)

def line_idx(event):
    return int(text.index(f"@0, {event.y}").split(".")[0])

def on_drag(event):
    i = line_idx(event)
    if i != prev_2_lines[1]:
        if i in prev_2_lines:
            do_toggle(prev_2_lines[1])
        do_toggle(i)
        prev_2_lines.append(i)

def on_b1press(event):
    i = line_idx(event)
    do_toggle(i)
    prev_2_lines.clear()
    prev_2_lines.extend([-1, i])

root = tk.Tk()

items = [f"Item {i+1}" for i in range(30)]

toggle = []
prev_2_lines = deque(maxlen=2)
prev_2_lines.extend([-1, -1])

text = tk.Text(root, wrap=tk.NONE)
text.bind("<B1-Motion>", on_drag)
text.bind("<Button-1>", on_b1press)

for item in items:
    text.insert(tk.END, item + "\n")
text.delete(text.index("end-1c linestart"), tk.END)

scrollbar = tk.Scrollbar(root, orient="vertical", command=text.yview)
text.configure(yscrollcommand=scrollbar.set)

text.pack(side=tk.LEFT, fill=tk.BOTH, expand=True)
scrollbar.pack(side=tk.RIGHT, fill=tk.Y)

text.tag_configure("highlight", foreground="black", background="light green")
text.tag_configure("sel", foreground="black", background="white")

root.mainloop()