insertText splits spans with id attribute in to two

[Jakub Ś]

Steps to reproduce

1. Prepare CKEditor with below configuration and content:

   var editor = CKEDITOR.replace( 'editor1', {
   	extraAllowedContent : 'span[id]',
   });
   
   <p><span class="marker" id="abc">test</span></p>
   

2. Put selection here and insert any special character # using Special Character dialog <p><span class="marker" id="abc">te^st</span></p> . Alternatively you can ma a selection and execute the following command in browser console CKEDITOR.insatnces.editor1.insertText( '#' )

Expected result

<p><span class="marker" id="abc">te#st</span></p>

Actual result

The span gets split in two: <p><span class="marker" id="abc">te</span><span class="marker">#st</span></p>

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

Problem can be reproduced at least from CKEditor 4.0.

[Mateusz Samsel]

PR: ​https://github.com/ckeditor/ckeditor-dev/pull/430