If additional JavaScript code is inserted into your mailings (or in your pages when using an embedded wysiwyg editor) check whether you have a third-party toolbar (such as Skype or Real Player) running in your browser.

We've had reports of these plugins inserting JavaScript dynamically into pages, especially when using Internet Explorer. It is even possible for code to be inserted if you close the toolbar but continue to run Skype as a service while you use the editor.

Uninstalling or deactivating these components while you use the wysiwyg editor should fix the problem.