Wouldn't it be nice to store the bar in a variable, then use page.overlay.remove(my_bar) to remove it?
What do you think?

store the bar in a variable, then use page.overlay.remove(my_bar) to remove it

absolutely, fantastic idea!

Here is the updated code, let me know if you approve and I will apply the changes.

`from time import sleep
import flet
from flet import ElevatedButton, ProgressBar

def main(page):
def button_click(e):
my_bar = ProgressBar()
page.overlay.append(my_bar)

 btn.disabled = True
 page.update()
 sleep(3)
 page.overlay.remove(my_bar)
 btn.disabled = False
 page.update()
btn = ElevatedButton("Do some lengthy task!", on_click=button_click)
page.add(btn)

flet.app(target=main)
`

Looks good to me.