Disabled textarea fields are not readOnly by default

[suzume]

According to CKEDITOR.config.readOnly, if not specified, it should check to see if the linked textarea has the disabled attribute. This is not currently happening.

[suzume]

Test case showing the problem

[Jakub Ś]

It seems that currently this works with disabled="disabled" but doesn't with sole disabled.

Code from ckeditor/code/ckeditor.js; Line 291

...CKEDITOR.ELEMENT_MODE_REPLACE ? editor.element.getAttribute( 'disabled' ) : false...

should probably be changed to

...CKEDITOR.ELEMENT_MODE_REPLACE ? editor.element.hasAttribute( 'disabled' ) : false...

Since CKE 3.x supported xhtml 1.1 this was valid approach. CKE 4.x supports mainly HTML5 thus both disabled="disabled" and disabled should be checked.

Problem can be reproduced from CKE 4.0 beta