Widget gets focus when typing with form input elements

[jacekbogdanski]

Type of report

Bug

Provide detailed reproduction steps (if any)

The issue is caused by the https://github.com/ckeditor/ckeditor4/blob/ad381679b4436f489a65f6f397680da338024b0f/core/selection.js#L942-L954f code which is supposed to prevent editing non-editable elements on Edge and IE. However, it also makes impossible editing correct form elements like textarea, input, etc.

You may have some issue reproducing test steps on IE as it doesn't fire keydown event when typing inside form elements, however, this code path is wrong for both Edge and IEs.

1. Open https://codepen.io/jacekbogdanski/pen/vYYXamd
2. Add test widget (no-icon button)
3. Focus the widget and start typing.

Expected result

Typed text is registered by widgets textarea.

Actual result

Widget gets focus on every keystroke which makes typing impossible.

Other details

• Browser: Edge, IE
• OS: Windows
• CKEditor version: at least 4.11.0