This is due to a major re-architecting, idle time spellchecker, which changes what and how text is checked, for input latency optimization.

Still, missing some checking is bad. We should enable the cold mode checking to ensure checking completeness.

This issue also exists when a field is updated via javascript with a large amount of text.

Manually using selection.modify with timeout's is just horrible.

https://jsfiddle.net/xpvt214o/45750/

Will fix this in M68.

mrforsythexeter@: Your case is a different issue. Chrome spellchecker never worked on script generated text. It currently only listens to user edit operations as a tradeoff between page responsiveness and checking completeless.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/72ac5c08820272be7452ebd9181f9308bf62a223

commit 72ac5c08820272be7452ebd9181f9308bf62a223
Author: Xiaocheng Hu <xiaochengh@chromium.org>
Date: Tue Apr 17 19:45:36 2018

[Spellcheck] Make cold mode idle time spellchecker less aggressive

This patch revises the cold mode idle time spellchecker that, it only
checks the editable element that is currently focused, instead of
checking the full document, so that the checker is less aggressive and
less resource consuming.

Bug:  824030 ,  716642 
Change-Id: I1361b53b4dd3513252ef50d0356497c0a4054ecd
Reviewed-on: https://chromium-review.googlesource.com/1014472
Commit-Queue: Xiaocheng Hu <xiaochengh@chromium.org>
Reviewed-by: Yoshifumi Inoue <yosin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#551442}
[add] https://crrev.com/72ac5c08820272be7452ebd9181f9308bf62a223/third_party/WebKit/LayoutTests/editing/spelling/cold_mode_multiline.html
[delete] https://crrev.com/3613946f7535f3a82c536e78ca80e95f04541b14/third_party/WebKit/LayoutTests/editing/spelling/cold_mode_static_page.html
[modify] https://crrev.com/72ac5c08820272be7452ebd9181f9308bf62a223/third_party/WebKit/LayoutTests/editing/spelling/spellcheck_test.html
[modify] https://crrev.com/72ac5c08820272be7452ebd9181f9308bf62a223/third_party/blink/renderer/core/editing/spellcheck/cold_mode_spell_check_requester.cc
[modify] https://crrev.com/72ac5c08820272be7452ebd9181f9308bf62a223/third_party/blink/renderer/core/editing/spellcheck/cold_mode_spell_check_requester.h
[modify] https://crrev.com/72ac5c08820272be7452ebd9181f9308bf62a223/third_party/blink/renderer/core/editing/spellcheck/idle_spell_check_callback.cc
[modify] https://crrev.com/72ac5c08820272be7452ebd9181f9308bf62a223/third_party/blink/renderer/core/editing/spellcheck/spell_check_requester.cc
[modify] https://crrev.com/72ac5c08820272be7452ebd9181f9308bf62a223/third_party/blink/renderer/core/editing/spellcheck/spell_check_requester.h

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/96b9e995718ccad040ad709f16c9b70cf58434d8

commit 96b9e995718ccad040ad709f16c9b70cf58434d8
Author: Xiaocheng Hu <xiaochengh@chromium.org>
Date: Wed Apr 18 02:56:21 2018

[Spellcheck] Enable cold mode idle time spellchecker in M68

As previously planned, we will enable cold mode checker as bug fix to
the current spellchecker, and will monitor its performance.

Bug:  824030 ,  716642 
Change-Id: Ie37a08fb6d5562d2f2ff2c2ac84e8033b6ffb776
Reviewed-on: https://chromium-review.googlesource.com/1015790
Reviewed-by: Kent Tamura <tkent@chromium.org>
Commit-Queue: Xiaocheng Hu <xiaochengh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#551558}
[modify] https://crrev.com/96b9e995718ccad040ad709f16c9b70cf58434d8/third_party/blink/renderer/platform/runtime_enabled_features.json5

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/322e3b5472bcdcfcef10f58d41506136132eb6fe

commit 322e3b5472bcdcfcef10f58d41506136132eb6fe
Author: Rune Lillesveen <futhark@chromium.org>
Date: Wed Apr 18 08:01:05 2018

Revert "[Spellcheck] Enable cold mode idle time spellchecker in M68"

This reverts commit 96b9e995718ccad040ad709f16c9b70cf58434d8.

Reason for revert: introduces memory leak on youtube.com test

First failling here:

https://ci.chromium.org/buildbot/chromium.linux/Leak%20Detection%20Linux/4115

Original change's description:
> [Spellcheck] Enable cold mode idle time spellchecker in M68
> 
> As previously planned, we will enable cold mode checker as bug fix to
> the current spellchecker, and will monitor its performance.
> 
> Bug:  824030 ,  716642 
> Change-Id: Ie37a08fb6d5562d2f2ff2c2ac84e8033b6ffb776
> Reviewed-on: https://chromium-review.googlesource.com/1015790
> Reviewed-by: Kent Tamura <tkent@chromium.org>
> Commit-Queue: Xiaocheng Hu <xiaochengh@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#551558}

TBR=yosin@chromium.org,tkent@chromium.org,xiaochengh@chromium.org

Change-Id: I03087aad24d41208a56aa1904eb55c719e771578
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug:  824030 ,  716642 
Reviewed-on: https://chromium-review.googlesource.com/1015363
Reviewed-by: Rune Lillesveen <futhark@chromium.org>
Commit-Queue: Rune Lillesveen <futhark@chromium.org>
Cr-Commit-Position: refs/heads/master@{#551610}
[modify] https://crrev.com/322e3b5472bcdcfcef10f58d41506136132eb6fe/third_party/blink/renderer/platform/runtime_enabled_features.json5

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/8712023f7d10238966ed56d02d27f10e02c8c394

commit 8712023f7d10238966ed56d02d27f10e02c8c394
Author: Xiaocheng Hu <xiaochengh@chromium.org>
Date: Fri Apr 20 05:55:49 2018

Reland "[Spellcheck] Enable cold mode idle time spellchecker in M68"

This is a reland of 96b9e995718ccad040ad709f16c9b70cf58434d8

Original change's description:
> [Spellcheck] Enable cold mode idle time spellchecker in M68
>
> As previously planned, we will enable cold mode checker as bug fix to
> the current spellchecker, and will monitor its performance.
>
> Bug:  824030 ,  716642 
> Change-Id: Ie37a08fb6d5562d2f2ff2c2ac84e8033b6ffb776
> Reviewed-on: https://chromium-review.googlesource.com/1015790
> Reviewed-by: Kent Tamura <tkent@chromium.org>
> Commit-Queue: Xiaocheng Hu <xiaochengh@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#551558}

Tbr: yosin@chromium.org, tkent@chromium.org
Bug:  824030 ,  716642 
Change-Id: I1d0a23c321432af6e5b74bd19eb4d7ab17db5220
Reviewed-on: https://chromium-review.googlesource.com/1020740
Reviewed-by: Xiaocheng Hu <xiaochengh@chromium.org>
Commit-Queue: Xiaocheng Hu <xiaochengh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#552270}
[modify] https://crrev.com/8712023f7d10238966ed56d02d27f10e02c8c394/third_party/blink/renderer/platform/runtime_enabled_features.json5

Fixed in M68, starting from 68.0.3402.0.

We are not merging it back to M67, due to the complexity in the implementation change. We also need more time to monitor it in M68.

Able to reproduce the issue on reported version hence verifying the fix on 68.0.3404.0 using Mac 10.13.3, Windows 10 and Ubuntu 17.10.

On pasting GoogleChrome-63.0.3205.0.dmg
GoogleChrome-63.0.3208.0.dmg
GoogleChrome-63.0.3213.0.dmg
GoogleChrome-63.0.3215.0.dmg
GoogleChrome-63.0.3220.0.dmg
GoogleChrome-63.0.3203.0.dmg
GoogleChrome-63.0.3228.0.dmg into report an issue dialog observed some delay in seeing underline below unselected lines. Attaching screencast of M-60 and latest M68 behavior.

@xiaochengh: Could you please let us know if this is the expected behavior.

Thanks!

Deleted: 824030_M68 vs M60.mp4 1.6 MB

	824030_M68 vs M60.mp4 1.6 MB View Download

sindhu.chelamcherla@: The new behavior you observed in M68 (requiring a delay to fully check the pasted content) is the expected behavior.