TYPO3 Core

so this is IE8? Does windows7 has a special IE or is it the same like on vista?

I have the same problem with IE 8 on a Linux server with Typo3 4.2.10 and a Windows XP client.
I guess its an installed extension...
... but I have no problems with the Mozilla browser... only with Internet Explorer 8.

Hm, using IE8 with Wine is probably not an everdays environment...
I could reproduce this with Windows XP and IE8 in regular mode - the result was the IE freezes.

No, I meant Typo3 4.2.10 an a Linux server. Not the IE. The IE on the Windows XP client.
Sorry for this misunderstanding.
Safari Browser looks fine too.
I have uploaded an example file:
http://www.quizpalme.de/fileadmin/ftp_upload/wrong-editor.htm
If you take a look at it, it looks fine. But in the backend it doesn´t looks good.
The first second it is OK too, but than the editor moves down.

If no one has this problem than leave it so. I am working now with Firefox.

I can confirm this on WIN XP with IE8 8.0.6001.18702 and TYPO3 4.3.3.

Additionally, the checkbox "Deactivate Editor" does not work:

Details zum Fehler auf der Webseite

Benutzer-Agent: Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 5.1; Trident/4.0; GTB6.4; .NET CLR 2.0.50727; .NET CLR 3.0.4506.2152; .NET CLR 3.5.30729; .NET CLR 1.1.4322)
Zeitstempel: Wed, 28 Apr 2010 10:32:18 UTC

Meldung: 'this.mirror.editor' ist Null oder kein Objekt
Zeile: 270
Zeichen: 5
Code: 0
URI: http://127.0.0.1/typo3/sysext/t3editor/jslib/t3editor.js

Resolved as duplicate of #11938.
The problem with deactivating the checkbox is a duplicate of #8245.

According to Tobias both should be fixed since 4.4.0beta2.