Well I suppose the first thing to ask is are you running any plugins that add to the editor? If so disable and see if it makes a difference.

Also before digging deeper, it might be worth switching to the default WP theme to make sure your theme is not interfering in any way.

Is everything up to date? WP, SP, plugins etc..

I just discovered this problem only occurs with Chrome (last vesrion).

It works perfectly with IE and Firefox.

OK, well the same still stands, is everything updated?

Also Chrome, when you say latest version are you referring to ‘Version 37.0.2062.103 m’ ?

And using the console, are you getting any errors in Chrome?

Yes, Chrome version is  37.0.2062.103 m.

Effectlivly, there are some errors in the console :

Uncaught ReferenceError: Jquery is not defined /wp-content/plugins/easy-shortcode-buttons/button.js:22
Deprecated TinyMCE API call: <target>.onInit.add(..)
Uncaught ReferenceError: purl is not defined forum-prive:1
Uncaught TypeError: Cannot read property ‘getRng’ of undefined

Well I wasn’t getting any errors in Firefox but now I am getting

TypeError: jspf(…).msDropDown is not a function     public:456
ReferenceError: Jquery is not defined                      button.js:22

Is ‘easy-shortcode-buttons’ as plugin you are running that add’s to the tinyMCE editor as I mentioned before?

Sorry, I was making some tests modifying head section. This is the cause of the errors you got with Firefox. 

I disabled easy-shortcode-buttons plugin. Now the errors in the console are :

eprecated TinyMCE API call: <target>.onInit.add(..) plugin.min.js?ver=4104-20140822:1
Uncaught ReferenceError: purl is not defined VM6704:1
Uncaught TypeError: Cannot read property ‘getRng’ of undefined

The problem comes from cforms plugin. If I disable it, there is no more error message and the editor is correctly displayed.

I made the change explained in this topic : http://wordpress.org/support/topic/plugin-black-studio-tinymce-widget-incompatibility-with-cforms

But it does not solve the problem. I suppose it solves it when TinyMCE is used directly in WordPress, not in Simple:Press.

Assuming – as Ike has asked – that all your code is up to date from WP to SP and all SP plugins – then this still looks like something that is adding something to the tinyMCE editor. Don’t forget we are referring here to something adding to the editor in the admin side of your site – I.e., for writing blog posts. If this is not written properly to only show up in the admin – it can badly affect the use of the editor on the front end. A lot of plugins that add buttons were also caught out when WP updated TinyMCE to version 4 (in WP 3.9) and some may still have not updated properly yet.

So – do you have anything active?

Might be worth adding that I can see and use the tinyMCE editor in both Firefox and Chrome with no problems now…

The solution : in cforms global settings, WP Editor Button support, uncheck “Enable TinyMCE & Code editor buttons”.

Thanks for your help.

 No problem…So all working?

It might be worth telling Oliver at cForms about this. It sounds like the tinyMCE side of cForms may be out of date with tinyMCE version 4.