WordPress MU

Why oh why can't I select the most recent versions in the drop-down? Oh well...

I have a problem with html-tag stripping on my wordpress-mu installation. Very simplified example:

I tried posting a new blog-entry using the standard-formatting available in word-press, no fancy plug-ins. All text-formatting, as well as links, images etc are stripped upon posting. The same applies to existing blog-entries. When I edit an existing entry it is stripped of all html-tags when I re-post it.

It seems like it is an error that kind of comes and goes, I'd suspect a server-provider error, but they deny that they have done any changes to their hosting-environment. Does anybody have any clue or idea to how to take it from here? How do I investigate this matter further?

Nobody has any ideas or suggestions? =) I know I put a post about this earlier, but the problem has re-appeared and it all started when I upgraded WordPress MU. Flawed database handling, encoding trouble somewhere? Anybody?!?

Well, I may just as well go on with this Hamlet-style monologue since someone else may stumble on the same problem, sooner or later. I have managed to conclude that the error is not with the server/db connection. I wrote a small sample script to test writing html-tagged text to the database from an input-form. And it worked, flawless!

So, the issue is apparently with the WordPress application. I am lost here guys, am I really the only one here experiencing this issue?

Okay, if you want something done, do it yourself. Is there a known flaw in the kses.php filtering? I commented out the following lines:

//add_filter('content_save_pre', 'wp_filter_post_kses');
//add_filter('excerpt_save_pre', 'wp_filter_post_kses');
//add_filter('content_filtered_save_pre', 'wp_filter_post_kses');

What did I just do, how important are these three lines? Anyhow, now it works, but can anyone, please ANYONE tell me what these filtering mechanism do? I suspect I might just have lost some important code-injection protection as well...