Is that line about text field? i.e. have you clicked that grey line to try typing some texts?

Oh yeah... Almost forgot. When I click the text field, or when I type something, the grey lines disappear. The lines reappear when I scroll up the field.

Is this still happening? I don't wanna install IE, but I probably could to actually look into fixing this, if it still needs it.

If you use the IE11 on either Windows 7, 8 or 10 (if 10, then enable IE11 via Edge), and if you enable the 2010 wikitext editor, you scroll up the editor and then see the grey lines. The grey lines immediately disappear when you move the mouse cursor or scroll down the editor.

Here's the screenshot:

All right, thanks. I'll look into this.

Also seriously what is the world coming to when working on IE bugs seems like a relaxing change of pace...

All right, can definitely reproduce on windows 7, but IE's dev tools are all broken, so I'm a bit limited at the moment...

(Can't reproduce on windows 10 because IE11 on that one seems to have decided it's actually IE6 and has refused to load half the stylesheets and any js. But the entire OS on that one is a bit fried, so I'm not going to read into that.)

It appears this is caused by an interaction between the Timeless text area box shadows and the WikiEditor toolbar styling. They're both fine by themselves.

Change 530650 had a related patch set uploaded (by Isarra; owner: Isarra):
[mediawiki/skins/Timeless@master] Fixes for IE11 and 9 too because fine we're going there and it's two lines

https://gerrit.wikimedia.org/r/530650

Change 530650 merged by jenkins-bot:
[mediawiki/skins/Timeless@master] Fix weird lines appearing in IE with Extension:WikiEditor

https://gerrit.wikimedia.org/r/530650

It won't actually hit enwp until the third or the fifth, based on the patch notes.

In T190991#5455572, @gh87 wrote:

Sorry, but the gerrit code didn't fix the problem. The issue still persists as seen below:

Issues are resolved when fully merged, not when deployed.