For a reason that I do not yet fully grasp, the problem was due to the \beamerdefaultoverlayspecification{<1->}
command that I had to put in my file to avoid having a bunch of "Reference" elements in the TOC. If I comment this line and fully adopt the Lyx-Beamer conventions (before that I was just using ERB for begin frame and end frame commands), my problem disappears. Very strange, but I was doing some unconventinal operations probably... So, another lesson I have learnt from here : "Don't be lazy, convert completely your latex file to Lyx's way, or you will get in trouble..." ;-) Regards, Murat -- Prof. Murat Yildizoglu Université Montesquieu Bordeaux IV GREThA (UMR CNRS 5113) Avenue Léon Duguit 33608 Pessac cedex France Bureau : F-331 yi...@u-bordeaux4.fr http://yildizoglu.info http://www.twitter.com/yildizoglu