Fenix: FNX2-13483 ⁃ [Bug] Discrepancy in behavior between top and bottom toolbar on feedbin.com

[serovar]

Steps to reproduce

Go to feedbin.com and login with your account, then scroll down through your feeds.

Expected behavior

When you scroll down, the bottom and the top toolbar have the same behavior (they are dynamic and autohide or they are pinned and do not move).

Actual behavior

When you scroll down, the bottom toolbar does is pinned and the top toolbar is dynamic.

Device information

• Android device: Pixel 2 XL, Android 10
• Fenix version: Nightly 200611 06:01, Build #2015745587

[ghost]

If I'm understanding correctly, I think this is intended behaviour for some sites according this comment: https://github.com/mozilla-mobile/fenix/issues/10073#issuecomment-639003404.

[serovar]

Maybe, but in that issue the first post says:

Expected behavior

Shouldn't trigger bottom toolbar

But in a site like feedbin the expected behavior is exactly the opposite (as with every other site that uses a bottom bar, like Twitter to say one), and it's handled perfectly fine by every Chromium-based browser without needing to pin the browser toolbar, so I don't see why Firefox should not, since I don't think Firefox developers are less capable then Chromium ones.

And to add to that, the toolbar is dynamic if set to the top.

[ghost]

@serovar See the comment not the post.
Bottom toolbar also doesn't hide when browsing through GitHub projects but does scroll in other places such as - Issues, Fenix GitHub home page.

Don't know if this will remain the case or change in future though.

[serovar]

I saw the comment, but my point is that this behavior is not expected on some kind of sites (like on feedbin), and it is now "intended behavior" only because it's a way to solve issues on other sites where instead the autohiding is effectively an unexpected behavior. Moreover, there is a discrepancy between the bottom tab and the top bar behaviors, where the first one is pinned and the second one is dynamic, but I've seen that because of some issues with the top dynamic bar this behavior is in discussion for it too.

I'll rename this issue and update the first comment to underline this discrepancy. I think the issue could be closed if they decide to pin the top bar too on this kind of sites, but that it should remain open if they decide to make to top bar dynamic, since it will introduce a different logic between bottom and top toolbar behavior for certain websites (such as feedbin).

[crisalis2]

The bottom bar not auto-hiding happens on quite a lot of sites for me (I'm on the latest Google Play Beta). For example, on Twitter and even right now here on Github.

[liuche]

I'm going to dupe this to #11389.

To address your comments: the reason the bottom bar isn't hiding is a result of GeckoView not handling embedded content scroll properly - see the linked bug. It's not because the bottom bar is pinned, that is the bug. You can follow along in the Bugzilla bug linked.