Editor enterMode: ENTER_BR doesn't strip leading whitespace immediately

[Steven Bone]

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
6. notice cursor/action move two spaces to the right

(space is trimmed on this keypress, and the next character is acted upon)

Expected result

leading whitespace should be trimmed on initial Enter keypress (like behavior when performing same action with ENTER_DIV and ENTER_P) Expected, demo'd with ENTER_DIV:

Actual result

leading whitespace is trimmed on Delete, as well as the '1' character.

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

• Chrome 56.0.2924.87
• OSX 10.12.3
• CKE 4.5.2 and 4.7.1

[Jakub Ś]

Problem can be reproduced from CKEditor 4.1.1 on Chrome in both Windows and Mac.

[Jakub Ś]

Similar can be applied to Fiefox and IE. Please see: #16929 and #16932