[ENTER_BR]: Enter hides space before text

[Jakub Ś]

Steps to reproduce

1. Set editor enterMode to ENTER_BR
2. In editor, enter text - 'Send to 123 Main St'
3. Place cursor immediately after 'to', before space
4. hit Enter key
5. on new line, hit Delete or Arrow Right

Expected result

Space should be visible and key press should either move cursor or delete the space.

Actual result

Notice that first key press does nothing and space before '123' is not visible.

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

Problem can't be reproduced in native contenteditable element.

[Jakub Ś]

Chrome and IE have similar problems: #16905 and #16932