Hi!By bisecting, I've determined the following bug is due to r25666 (http://www.lyx.org/trac/changeset/25666).
This is the bug: the attached LyX file (r25666-bug.lyx), when opened in r25665, correctly produces the dvi output correct.dvi; when opened in r25666, however, the output is incorrect.dvi.
The thing is this: the file can initially be created also in r25666, and then it displays correctly. If you then save it, the saved file is identical to that created in r25665. But when you load it, the layout is no longer preserved inside the cell; and there is no option to change the layout: the layout box is now grayed out, and trying to set itemize with 'Alt-p i' produces the message 'Command disabled' in the status bar.
Thanks! Dov
r25666-bug.lyx
Description: application/lyx
correct.dvi
Description: TeX dvi file
incorrect.dvi
Description: TeX dvi file