TYPO3 Core

this is most likely not a BUG but some misconfiguration that can happen real easily. ;(
Are you using css_styled_content?
If then there is some configuration added in RTE.tt_content.bodytext This iconfiguration is more specific than the one in the default-key. Therefor default wont be taken into consideration
Plz put the config in the key:
RTE.tt_content.bodytext.proc

i've tried
RTE.tt_content.bodytext{
proc.overruleMode = ts_css
proc.preserveTables = 1
typohead=1
typolist=1
proc.dontConvBRtoParagraph=1
showButtons = cut, copy, paste, formatblock, class, fontstyle, fontsize, textcolor, bold, italic, underline, left, center, right, orderedlist, unorderedlist,outdent, indent ,link ,table, bgcolor, image, emoticon, line, user, chMode,lefttoright, righttoleft, justifyfull, strikethrough, superscript, subscript
allowTagsInTypolists = br,b,i,u,a,img
allowTags = br, table, tr, th, td, h1, h2, h3, h4, h5, h6, div, p, span, ul, ol, li, pre, blockquote, strong, em, b, i, u, sub, sup, strike, a, img,nobr, hr, center
}

AND

RTE.default{
proc.overruleMode = ts_css
proc.preserveTables = 1
typohead=1
typolist=1
dontConvBRtoParagraph=1
showButtons = cut, copy, paste, formatblock, class, fontstyle, fontsize, textcolor, bold, italic, underline, left, center, right, orderedlist, unorderedlist,outdent, indent ,link ,table, bgcolor, image, emoticon, line, user, chMode,lefttoright, righttoleft, justifyfull, strikethrough, superscript, subscript
allowTagsInTypolists = br,b,i,u,a,img
allowTags = br, table, tr, th, td, h1, h2, h3, h4, h5, h6, div, p, span, ul, ol, li, pre, blockquote, strong, em, b, i, u, sub, sup, strike, a, img,nobr, hr, center
}
RTE.tt_content.bodytext.proc{
dontConvBRtoParagraph=1
}

-----------
none seem to work. I'm using css_styled_content

I am sorry, there has been an error in my first note.
It should read:

RTE.config.tt_content.bodytext.proc
(+config)

plz consult the manul
http://typo3.org/documentation/document-library/doc_core_api/Page_TSconfig-1/
you are strongly advised to do such things before posting bugs.

Thx,
Peter

Yeah, now it works. then the bug was only in my head.