Clicking on tab's top doesn't select it sometimes in a maximized window

[ilyaigpetrov]

Description

In a brave maximized window clicking on the very top of a tab doesn't select it sometimes.
On the gif attached you may see that tabs lose highlight while I keep the cursor at the top of the screen all the time.

Steps to Reproduce

1. Open brave in a maximized window with some tabs open (pinned or not).
2. Move cursor to the very top of a tab, move it left or right slightly, see tab loses or gains highlights repeatedly.
3. See that clicking a tab when it loses highlight doesn't select it.

Actual result:

Tab is not selected on a click on its top.

Expected result:

Tab must be selected on a click on its top.

Reproduces how often:

Every time I use Brave.

Brave version (brave://version info)

Brave 1.16.48 Chromium: 86.0.4240.55 (Official Build) beta (64-bit)
Revision a6d625ef6f7fe8ea0675f1cf759155a05ee1be40-refs/branch-heads/4240@{#953}
OS Linux
JavaScript V8 8.6.395.10
Flash (Disabled)
User Agent Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/86.0.4240.55 Safari/537.36
Command Line /opt/brave.com/brave-beta/brave --enable-dom-distiller --disable-domain-reliability --no-pings --extension-content-verification=enforce_strict --extensions-install-verification=enforce --origin-trial-public-key=bYUKPJoPnCxeNvu72j4EmPuK7tr1PAC7SHh8ld9Mw3E=,fMS4mpO6buLQ/QMd+zJmxzty/VQ6B1EUZqoCU04zoRU= --sync-url=https://sync-v2.brave.com/v2 --lso-url=https://no-thanks.invalid --enable-features=AutoupgradeMixedContent,PassiveMixedContentWarning,MixedContentSiteSetting,DnsOverHttps,OmniboxContextMenuShowFullUrls,LegacyTLSEnforced,WebUIDarkMode,PasswordImport,ReducedReferrerGranularity,PrefetchPrivacyChanges --disable-features=PrivacySettingsRedesign,NotificationTriggers,TextFragmentAnchor,AutofillEnableAccountWalletStorage,AllowPopupsDuringPageUnload,SmsReceiver,TabHoverCards,VideoPlaybackQuality,AutofillServerCommunication,PasswordCheck,SafeBrowsingEnhancedProtection --flag-switches-begin --flag-switches-end
Executable Path /opt/brave.com/brave-beta/brave
Profile Path /home/ilyaigpetrov/.config/BraveSoftware/Brave-Browser-Beta/Default

Version/Channel Information:

Tested and happens on beta channel.

• Can you reproduce this issue with the current release?
  No, no such problem in:
  Brave | 1.14.84 Chromium: 85.0.4183.121 (Official Build) (64-bit)
  Revision | a81aa729a8e1fd413943a339393c82e7b8055ddc-refs/branch-heads/4183@{DNS over HTTPS #1864}
  OS | Linux
• Can you reproduce this issue with the beta channel?
  Yes.
• Can you reproduce this issue with the nightly channel?
  Yes, reproducible on:
  Brave | 1.17.11 Chromium: 86.0.4240.68 (Official Build) nightly (64-bit)
  Revision | ad72ee9aa8e15ed300df1238e76c7a8f4d686f97-refs/branch-heads/4240@{Shields button pops up when search engine option is shown on omnibox #1097}
  OS | Linux

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?

Not reproducible on:

Google Chrome | 85.0.4183.15 (Official Build) dev (64-bit)
Revision | 53db90617a040f373db04863f92240061be06d3d-refs/branch-heads/4183@{#221}
OS : Linux

Miscellaneous Information:

Linux Mint 20 Xfce Edtition

The Gif

[Wobblystep]

Happens to me as well, on Arch Linux, in XFCE desktop with X11, now that i have updated from 1.14.84 64-bit release (official precompiled binary) to Version 1.15.72 64-bit release (official precompiled binary).
Also tested with Cinnamon default theme and some other most popular.

The same happens with a new profile, and no theme option makes any difference.

[FrozenAlex]

I have the same issue on arch linux KDE on 1.15.72 Chromium: 86.0.4240.75 (Official Build)

[Wobblystep]

I was able to work around something similar, but for MATE panel, which also uses GTK3.
By adding "export GDK_CORE_DEVICE_EVENTS=1" to my bash profile (mate-desktop/mate-panel#940) the edge flickering input problem was fixed there.

But it doesn't affect the Brave problem, even if I run the brave binary directly with that variable set in front.
Also tried with disabled sandboxing.

[ilyaigpetrov]

This bug is observed not only in Brave but also in Chromium:

86.0.4240.198 (Official Build) for Linux Mint (64-bit)
Revision | d8a506935fc2273cfbac5e5b629d74917d9119c7-refs/branch-heads/4240@{#1431}
OS | Linux

[ilyaigpetrov]

Seems to be fixed in:

1.18.57 Chromium: 87.0.4280.66 (Official Build) beta (64-bit)
Revision | fd98a29dd59b36f71e4741332c9ad5bda42094bf-refs/branch-heads/4280@{#1432}
OS | Linux

Please, reopen this issue if it becomes reproducible again in Brave Beta or Brave Nightly.