(I think that is what happened)
So that my clients would see some styling in the WP Visual editor, using this tutorial http://www.jleuze.com/add-a-themes-css-style-to-the-visual-editor, I would do this:
1) In the child theme functions.php, I would add:
// Add styles to the WYSIWYG editor
2) In the style.css file, add something like this and more to make styles appear in Visual Editor.
border-top: 2px solid #000000;
padding: 1em 0 0;
But suddenly I noticed that all stopped working. And I think it was when I updated to WP 3.4
Googling, I found this http://queryposts.com/function/add_editor_style/ and this http://wpseek.com/add_editor_style/ which both say something about a editor-style-rtl.css style sheet. But I can not figure out what I should be doing. I just know that WYSIWYG styles are not working in the Visual editor.
Checking again, I see that it is broken on two sites with Thematic child themes. Not broken on a non Thematic site.
What should I be doing?
Grégory Viguier answers:
Do you use parameters in your url ?
Something like add_editor_style('style.css?v=3');
If you do, I made a little tweak last night: http://scri.in/aes34
Sorry it's in french, but basically you need to replace add_editor_style('style.css?v=3'); with my function:
w3p_add_editor_style( array('style.css?v=3', style2.css?v=12) );
At least you can get a try and wait for the fix in the next WP update.
EDIT: the function must be placed in the functions.php file of your theme.