Navbar flashes/slides down on click

can you please record a video of the issue?

provide more details:
- browser type/version/OS
- mobile type/version
- any customisations of the theme?

Sorry for the slow response and thanks for following up. I have used this Bootstrap 5 theme on D9 and D10 and in both cases the navbar flashes white and appears to rapidly slide down into place. So far it seems to only affect Chrome/Brave and Opera. Firefox and Edge did not exhibit the same problem.

Mobilewise I have only tested Chrome and Safari and it's fine on either.

When I first noticed this I was on D10 and had done quite a bit of theme customization so I didn't want to jump to conclusions. Since then I have installed in on more than one D10 server and a D9 server and it exhibited the problem immediately after I had added a menu link to the navbar.

@GuyManDude, I want to help you, but I can't reproduce this problem. Could you please help me with this?

Does this problem occur for all users or only for the admin/anonymous/authorized user?
Do you add the link to the main menu or some other way?
Perhaps you can provide your procedure?

I added the menu link using the /admin/structure/menu method. It does it regardless of the user I am logged in with.

Could you please provide a video?
Unfortunately, the problem is not reproducible.

You'll have to download it to view it. Link

@GuyManDude unfortunately, this problem occurs in all themes when you have a toolbar, as the height for it is calculated using js.
In general, it looks more like a toolbar issue #2542050: Toolbar implementation creates super annoying re-rendering. → .

@Abyss thanks.
@GuyManDude can you test it without being logged in?

@VladimirAus It only flashes when I am logged in. That's an interesting find!