toolbar remains visible when html component is fullscreen

[ghost]

I've checked to see if this has been logged, but could not find anything.

Description

when requesting a video component (or other HTML component to go fullscreen, the toolbar (with tabs) is visible on the screen. This has been observed on macOS - no other systems have been tested.

Steps to Reproduce

1. go to youtube
2. select a video and play it
3. click the video's fullscreen button
4. the video goes fullscreen and the toolbar is visible

Actual result:

Expected result:

the toolbar should not be visible unless I move the mouse to the top of the screen (previous behaviour)

Reproduces how often:

Easily, reproducible every time

Brave version (brave://version info)

Brave 1.25.70 Chromium: 91.0.4472.77 (Official Build) (x86_64)
Revision 1cecd5c8a856bc2a5adda436e7b84d8d21b339b6-refs/branch-heads/4472@{#1246}
OS macOS Version 10.15.7 (Build 19H1217)
JavaScript V8 9.1.269.28
User agent Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/91.0.4472.77 Safari/537.36
Command Line /Applications/Brave Browser.app/Contents/MacOS/Brave Browser --enable-dom-distiller --disable-domain-reliability --no-pings --origin-trial-public-key=bYUKPJoPnCxeNvu72j4EmPuK7tr1PAC7SHh8ld9Mw3E=,fMS4mpO6buLQ/QMd+zJmxzty/VQ6B1EUZqoCU04zoRU= --sync-url=https://sync-v2.brave.com/v2 --lso-url=https://no-thanks.invalid --variations-server-url=https://variations.brave.com/seed --enable-features=WebUIDarkMode,PrefetchPrivacyChanges,PasswordImport,ReducedReferrerGranularity,LegacyTLSEnforced,AutoupgradeMixedContent,SafetyTip --disable-features=WebOTP,HandwritingRecognitionWebPlatformApi,TrustTokens,DirectSockets,SharingQRCodeGenerator,IdleDetection,AutofillEnableAccountWalletStorage,FledgeInterestGroupAPI,EnableProfilePickerOnStartup,TextFragmentAnchor,NotificationTriggers,TabHoverCards,InterestCohortFeaturePolicy,FledgeInterestGroups,HandwritingRecognitionWebPlatformApiFinch,FlocIdComputedEventLogging,LangClientHintHeader,SubresourceWebBundles,NetworkTimeServiceQuerying,FederatedLearningOfCohorts,AutofillServerCommunication,LiveCaption,SignedExchangeSubresourcePrefetch,InterestCohortAPIOriginTrial,FirstPartySets,SignedExchangePrefetchCacheForNavigations --flag-switches-begin --enable-features=WebUIDarkMode,PrefetchPrivacyChanges,PasswordImport,ReducedReferrerGranularity,LegacyTLSEnforced,AutoupgradeMixedContent,SafetyTip,ImmersiveFullscreen --flag-switches-end
Executable Path /Applications/Brave Browser.app/Contents/MacOS/Brave Browser
Profile Path /Users/phartshorn/Library/Application Support/BraveSoftware/Brave-Browser/Default
Variations 8eed39a1-b5b19078
1f0eeff1-46c97c06
aed3cac0-3f4a17df
7146a73c-3f4a17df
c63a3c82-3f4a17df

Version/Channel Information:

• Can you reproduce this issue with the current release?
• Can you reproduce this issue with the beta channel?
• Can you reproduce this issue with the nightly channel?

Other Additional Information:

• Does the issue resolve itself when disabling Brave Shields?
• Does the issue resolve itself when disabling Brave Rewards?
• Is the issue reproducible on the latest version of Chrome?

Miscellaneous Information:

• When clicking on some elements in the toolbar (like the down arrow on the right to display the tab list and recently closed tabs) the click action is not consumed by the toolbar, but is received by the HTML.
• This occurs on all video sites, not just youtube.

[ghost]

I've just booted into my work computer that still has version 1.25.68 and the fullscreen issue does not occur.

[ghost]

Problem solved... enable-immersive-fullscreen-toolbar was enabled.

Steps to resolve:

1. load brave://flags/ in a brave browser window
2. search for "enable-immersive-fullscreen-toolbar"
3. ensure it is set to "Default"