I'm writting my thesis with the classicalthesis package. I have a problem with long chapter titles being too long for headings. For that reason I use the short title option (in Lyx). By definition the short titles are used for the Table of Content but I want them to be long in the TOC. I read
http://latex-community.org/forum/viewtopic.php?f=19&t=14166
and I used the titlesec package with the "toctitles" option in the (LaTeX) preamble in LyX, but I get an error message form Lyx:
LaTeX Error: Option clash for package titlesec. Use of \@chapter doesn't match its definition.
Sorry I dont know how to attach example files in my question, I attach two pictures:
Please see the content list
titlesecshould not be used with KOMA. To sum it up: We need a compilable example to play with. – Johannes_B Dec 10 '14 at 09:51