djk1

foun the solution here:
http://ww.wp.xz.cn/support/topic/visualhtml-toggle-no-longer-works-in-33/page/2?replies=44 :

Hi Sebaztian,

I have experienced problems and all of the solutions offered didn’t work. What DOES WORK for me is to change the WordPress language define settings in the wp-config.php file. My problem was that my install language was defined as German and it caused problems. The moment I defined the language as English (or any other language apart from German), the problem went away. As far as I know, there is no language defined in the usual wp-config and so the system defaults to ENglish (I could be wrong).

Go into the wp-config file and insert:
define (‘WPLANG’, ‘xx_XX’);

changing xx_XX to the language you want. If there are problems change it to ENglish (en_EN)

You can see your language setting here:
http://codex.ww.wp.xz.cn/Installing_WordPress_in_Your_Language

According to sources, WordPress is aware of this and is looking into it.

Hope it works for you!

Did work for me. Not only repaired my visual editor but my change header problems as well.
Thanks so much!

got the same problem. deactivated all my plugins and it did help some pages yet not all:
– some small pages that already showed in edit mode but without visual editor now are completely visual as it should
– other bigger pages that even didn’t go to edit mode now are in edit mode but still without visual editor and inactive html editor. if I select all in wysiwyg mode then I get to see html content, see http://cred-it.com/voorbeeld-pagina/screenshot-editor-3

switched to Twenty Eleven theme but no effect there.

what else can I try?

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