Am Montag 17 Februar 2014, 11:42:25 schrieb Richard Heck:
> This appears to be a beamer limitation. I see the same problem using one
> of the example files from:
>
> http://www.informatik.uni-freiburg.de/~frank/ENG/latex-course/latex-course-3
> /latex-course-3_en.html
>
> and trying to emphasize some section text. Though, if I add \protect, it
> at least compiles.
Yes, it's a limitation, caused by the specific way \emph is implemented in
beamer (it is overlay-aware, so you can also do \emph<2-3>{foo}).
As Richard writes, you need to \protect it. With LyX 2.1, just use Edit > Text
Style > Emphasized instead of the normal emphasizing. LyX will automatically
protect that. Also, it features overlays via optional argument.
This is also documented in the new LyX beamer manual (also 2.1).
Jürgen
