How to make my pygame game window resizeable?

Question

When I run this code the resizeable option is available but when I click on it to maximize the screen, there is this weird white outline that appears. How would I fix it?.

import pygame
pygame.init()
screen = pygame.display.set_mode((900, 500), pygame.RESIZABLE)


running = True
while running:
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            running = False
    pygame.display.update()

Answer 1

You have to recreate the display Surface in the VIDEORESIZE event (see pygame.event):

import pygame
pygame.init()
screen = pygame.display.set_mode((900, 500), pygame.RESIZABLE)

running = True
while running:
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            running = False
        elif event.type == pygame.VIDEORESIZE:
            screen = pygame.display.set_mode(event.size, pygame.RESIZABLE)
    pygame.display.update()