TYPO3 Core

If I sort my buttons like this (it was copied from the manual):
RTE.default.toolbarOrder = blockstylelabel, blockstyle, space, formatblock, bar, linebreak, fontstyle, space, fontsize, space, textstylelabel, textstyle, bar, bold, italic, underline, bar, linebreak, strikethrough, subscript, superscript, bar, lefttoright, righttoleft, bar, left, center, right, justifyfull, bar, orderedlist, unorderedlist, outdent, indent, bar, textcolor, bgcolor, textindicator, bar, emoticon, insertcharacter, line, link, image, table, user, acronym, bar, findreplace, spellcheck, bar, chMode, inserttag, removeformat, bar, copy, cut, paste, bar, undo, redo, bar, showhelp, about, linebreak, toggleborders, bar, tableproperties, bar, rowproperties, rowinsertabove, rowinsertunder, rowdelete, rowsplit, bar, columninsertbefore, columninsertafter, columndelete, columnsplit, bar, cellproperties, cellinsertbefore, cellinsertafter, celldelete, cellsplit, cellmerge

There is all right ... but if I delete the "linebreak" before the "strikethrough" there is the bug, shown in addet pictures.

htmlArea RTE
Version 1.7.5

Typo3
Version 4.2.1
(issue imported from #M9618)