[Edge] Dropped support for `setActive` (used to focus editor in some cases).

[kkrzton]

The parent task is #14819.

The newest version of Edge browser (Edge 38.14393, EdgeHTML 14.14393) dropped support for setActive which ​is used to focus editor in some cases (e.g. divarea plugin) to ​prevent unwanted scrolling.

While focus should be probably used in this case, it causes this unwanted scrolling so some workaround should be also applied.

Steps to reproduce ¶

1. Go to plugins/divarea/samples/divarea.html.
2. Run CKEDITOR.instances.editor1.editable().find('table').getItem(0).scrollIntoView() in the console.
3. Run CKEDITOR.instances.editor1.focus() in the console.

To check if editor was focused use document.activeElement.

Expected result ¶

Editor should be focused without scrolling.

Actual result ¶

Editor is focused and scrolled to the top.

Other details (browser, OS, CKEditor version, installed plugins) ¶

Edge (Edge 38.14393, EdgeHTML 14.14393)

---

This issue causes some unit tests fails in:

• tests/core/config/inline
• tests/core/dom/documentfragment
• tests/core/editable/domfix2
• tests/core/editable/wysiwyg
• tests/core/editor/title
• tests/core/filter/editor
• tests/core/selection/editor
• tests/core/selection/fake
• tests/plugins/autoembed/autoembednotifications
• tests/plugins/floatingspace/floatingspace
• tests/plugins/image/image
• tests/plugins/mathjax/mathjax-mock
• tests/plugins/pastefromword/pastefromword
• tests/plugins/sourcearea/source
• tests/plugins/uploadimage/uploadimage
• tests/tickets/11500/1

At least using focus (instead of setActive) fixes the tests but scrolling problem remains.

[kkrzton]

After further investigating this issue it seems that not the native focus is the reason of unwanted scrolling (​http://jsfiddle.net/f1ames/v1bbspoe/) but some custom focus post-logic.

[kkrzton]

This one was a little tricky to track, but:

• The scrolling is caused by a native focus call (not by a custom logic as I assumed in a previous comment).
• The scrolling effect does not occur when debugging via dev console (active breakpoints - pausing the code execution).
• The scrolling occurs only when focus is executed via code (not initiated by user interaction) - that's why here ​http://jsfiddle.net/f1ames/v1bbspoe/1 clicking button does not cause scrolling but timeout call does.
• The scroll caused by focus happens in async way so the new scrollTop value should be retrieved in a deferred way after focus is called.

[kkrzton]

Pushed fix to ​t/14825.

One thing to notice is that the scroll happens only if editor is focused for the first time. If it was focused before, refocusing works as expected.

[Tomasz Jakut]

Fixed with ​git:3f95046.