Capitalization of "true" in contenteditable makes CKEditor to not load.

[francisco]

Steps to reproduce. In a normal, working installation put this code:

<div contenteditable = "true"></div>

and CKEditor will load. In the same installation, changing only that line to this:

<div contenteditable = "TRUE"></div>

Will make it not to load. This is not desirable since, in the second case, the HTML is still parsed correctly so you get an editable div without CKEditor.

Browser and OS (irrelevant?): Firefox 22.0 on Ubuntu 13.04 Chromium 28.0 on Ubuntu 13.04

Test case. Just write this code, load the page and see how they load differently:

<div contenteditable = "TRUE">
  Error! In this div the CKEditor won't load
</div><br>
<div contenteditable = "true">
  Success! In this div the CKEditor will load
</div>

[Olek Nowodziński]

This issue could be resolved in one of these ways:

1. Making several changes in different parts of the editor to consider contenteditable value as lower-case (in CKEDITOR.inlineAll, CKEDITOR.dom.node.isReadOnly and more).
2. Making CKEDITOR.dom.element.getAttribute() always return a lower-cased value of contenteditable attribute.
3. Make CKEDITOR.dom.element.getAttribute() return a lower-case strings for all attributes.

Solutions 1. and 2. would only bring inconsistency into editor's API by making contenteditable a "special, privileged attribute".

Solution 3. is not only a drastic change but it also touches other methods (like CKEDITOR.dom.element.data). Also if we changed the way the method works, other methods like getStyle would also need to return a lower-cased strings to keep API consistent.

Therefore there's no good way to solve the issue other than generating a lower-case attribute values on the server-side.

[Piotrek Koszuliński]

I was hesitating whether we should accept this issue. After a discussion we decided that we don't want to fix it. There are two reasons - it is a good practice to write attributes' values in lower case and it would require overcomplicating editor's code to handle upper cased ones.