How to add different background colors to different selection options in ttk.Combobox?

I want to add different colors to different selections in Combobox. I found questions about changing the overall background color, but not per entry.

I'm attaching some examples below.

The Ttk Combobox does not supports that feature. So it's recommended to implement a custom widget with the Entry and Menu as in the ctk_combobox.py.

But if you don't mind hacking the Tk, you can try like the following.(It may break in the future.)

import tkinter as tk
from tkinter import ttk

root = tk.Tk()

combo = ttk.Combobox(root, values = ['red', 'green', 'blue'], state = 'readonly')
combo.pack()

def configure_items():
    lines = [f'set popdown [ttk::combobox::PopdownWindow {combo}]']
    for i, v in enumerate(combo['values']):
        lines.append(f'$popdown.f.l itemconfigure {i} -background {v}')
    root.tk.eval('\n'.join(lines))
combo.configure(postcommand=lambda: root.after_idle(configure_items))

root.mainloop()

To understand the above code, you need to see the combobox.tcl and the listbox reference.