Please see https://cs.chromium.org/chromium/src/third_party/WebKit/LayoutTests/platform/linux/paint/selection/text-selection-newline-mixed-ltr-rtl-expected.png?q=platform/linux/paint/selection/text-selection-newline-mixed-ltr-rtl-expected.png+package:%5Echromium$&l=1. The dark red pixels are under-invalidated.

The cause might be that visual overflow of line box doesn't cover all glyph overflows. drott@ can you take a look?

(BTW, sometimes I saw residues near the bottom of glyphs in the edit box of bugs.chromium.org. Not sure if this is the same issue.)

I just reproduced a glyph overflow issue on Pixel ChromeBook:

1. Input some text containing 'y', 'g' etc. in a multiline edit box in crbug.com or codereview.chromium.org.
2. Move caret to the beginning of the line and delete some characters.

Actual: some pixels at the bottom are left at their original places. The spellcheck marks also have the same problem.

Deleted: Screenshot 2017-04-03 at 7.50.03 PM.png 19.7 KB

	Screenshot 2017-04-03 at 7.50.03 PM.png 19.7 KB View Download

Issue 706298 has been merged into this issue.

The following info is from bug 706298:

The issue also reproduces with the attached test case on Android Chrome 57+ and WebView:
1. Push the file onto device: adb push textarea.html /sdcard/
2. Open the file in chrome (/sdcard/textarea.html)
3. Zoom in the page to maximum
4. Input some indic characters with high ascend and delete them

Deleted: textarea.html 56 bytes

textarea.html 56 bytes View Download

As one of my CLs exposed this bug in more cases and is treated as a regression in bug 706298, I'll try to fix this bug.

I'm separating the two bugs because the fix for bug 706298 might be a workaround, while this bug is for a better fix to the general problem of glyph overflows.

See also  http://crbug.com/674279#c17  which could be related/helpful.

I currently don't have a lot of bandwidth to look into this. If someone wants to take over, please feel free to take the issue.

This issue has been Available for over a year. If it's no longer important or seems unlikely to be fixed, please consider closing it out. If it is important, please re-triage the issue.

Sorry for the inconvenience if the bug really should have been left as Available.

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot