Editor may be assuming presence of editable too optimistically.

[Jakub Ś]

Steps to reproduce

Sometimes in Bink and Webkit browsers when dealing with multiple editors you may encounter a situation where editable is not present yet.

URI: core/dom/element.js
Line: 1986

Code: if ( editable.equals( this )

editable.contains( this ) ) {

Expected result

No error should be thrown.

Actual result

In these rare cases error might get thrown.

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

Problem occurs in Blink and Webkit browsers and simple null check should do the trick.