[Typo3-dev] is this a bug in CSS_styled content ?

[Roberto Saccon]

Hello everyone
whenever I use a plugin which has CSS stylesheets, the header-content of 
the plugin appears twice on my page, I have experienced this with the 
new ogin box and the newsletter subscription. Is this a bug and does 
there exist a workaround or is this just a somehow a misconfiguration at 
my setup (Version 3.5)

regards
Roberto

P.S.: this is my first Post at typo3-maillist, If I have chosen the 
wrong list, pls let me know.