preview of tikz pictures

[Paolo M]

Here enclosed, two lyx docs:  expo2 and expo3 differing just in one
(commented out) line in their preamble:
expo2: %\lfoot{  }
expo3: %\lfoot{ è  }

Both docs produce their pdf file but the weird thing is that, in expo3,
picture cannot be previewed in lyx.
How can a comment in preamble affect preview?

Any ideas?

thank you

Paolo M.

-- 
--- Paolo M. Pumilia - 347 231 54 96.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.lyx.org/pipermail/lyx-users/attachments/20230323/657fa00c/attachment-0001.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: espo3.lyx
Type: application/x-lyx
Size: 4432 bytes
Desc: not available
URL: <http://lists.lyx.org/pipermail/lyx-users/attachments/20230323/657fa00c/attachment-0002.lyx>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: espo2.lyx
Type: application/x-lyx
Size: 4430 bytes
Desc: not available
URL: <http://lists.lyx.org/pipermail/lyx-users/attachments/20230323/657fa00c/attachment-0003.lyx>