change text background twice, cause the color to be lost

[Anas]

Steps to reproduce

Simplified the test case:

1. Open the editor and set the following source:

<p><span style="color:#00FF00">Sample line</span></p>

1. Put the selection in the middle of line: Sample ^line.
2. Apply red font color using the "Text Color" button.

Expected:

Red font color should be applied only to what you're about to write.

Actual:

Text color of the paragraph is removed.

Additional notes:

1. Interesting note is that span[style="color:#FF0000;"] has been created for the red font color, but the selection is not placed within that span (that's the case at least for Chrome, because IE11 is able to put the selection correctly).
2. This issue might be similar to #13821.
3. Could be reproduced with Chrome, Firefox and IE11.

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

Chrome Version 48.0.2564.97 m Win 8.1 CKEditor version 4.5.5 (also active on the live website and the nightly build). You can use the default config on the website demo, also i Attached is my build-config.js.

[Marek Lewandowski]

Simplified test case.

[Marek Lewandowski]

I can reproduce issue at least since 4.0.0.

[Jakub Ś]

This issue is in fact a duplicate of #8934 which is very similar to #10650 (These two are however not duplicates - they may have same source of the problem but TC and browsers differ).

Another ticket worth mentioning is #10995