@gh87 Were you able to edit the page though?

I thought I could edit only the top of the source code.

Indeed, if I scroll down the window and then click on the content, the page still goes back up. However, I pressed PageUp or PageDown and any other keys, and I can type anything.

If I were to continue using the mode in IE11, I would rely more on a keyboard to scroll down and then type anything. Otherwise, if I click the editing window with a mouse, the page goes back up to the beginning, so I have to use the PageDown to go back to where I left off.

Also, I found out that performing either Ctrl+X or Ctrl+C might be okay. However, once I perform the Ctrl+V, the content won't break a line.

I can confirm this bug on IE11. Steps to reproduce:

1. Open a random article in WikiEditor with syntax highlighting enabled
2. Scroll down and click somewhere in the article text body.
3. The texture immediately scrolls back up to the top but your cursor remains at the place you clicked.
4. Hit enter/and or start to type, you get scrolled back to the place you were at.

I could not reproduce this behavior in Edge but I saw a somewhat different bug in Edge where the cursor moves to the beginning of the article window. I'll file a task for it.

Regarding Edge, we've got conflicting reports here. The task title says "IE and Edge", but the description says "Problem does not occur in Edge". Is Edge supposed to be affected or not?

I tried it out myself, and I could only reproduce the "textarea scrolls back to top" in IE, not Edge.

I saw a somewhat different bug in Edge where the cursor moves to the beginning of the article window. I'll file a task for it.

I couldn't repro this either. I'm using Windows 10.

It looks like Niharika opened a separate task (T191093) then merged them.

Either we need to fix this for IE11 or we should disable CodeMirror on IE11 for all editors (2017, 2010, and 2006).

I think I can confirm this is not a bug in CodeMirror, so to speak. CodeMirror as you may know reimplements everything the browser does natively, including scrolling. If I add a bunch of logging to the code, I can see it is setting the correct value for the scroll position when you click in the textarea, then those same methods get called again but with a value of 0 (because there's also a scroll event listener). That tells me CodeMirror is at least trying to do the right thing. Why IE jumps you to the top I still don't know :(

I should mention that although the scroll position gets reset, the cursor is still in the right place. Once you start typing the scroll position goes back to where the cursor is. Annoying, yes, but it is at least functional.

I don't have a windows machine or environment handy so I can't easily test this — the purpose of this ticket is to make the behavior of the editor the exact same with CodeMirror as it is without CodeMirror.

Due to the difficulty of these defects, the minimal usage of IE, and the fact this is an opt-in feature, the Community Tech team will not be fixing any more IE bugs for CodeMirror.