Instant previews not showing

[Daniel]

On 2020-04-15 10:38, Andrew Parsloe wrote:
> On 15/04/2020 8:21 pm, Daniel wrote:
>> Hi,
>>
>> Is there a way to see why instant previews fail to generate?
>>
>> I have a document that compiles fine but the instant previews in it 
>> don't. In other documents the previews just work fine. So, there must 
>> be a particular problem with this one (which is a child of a master 
>> document).
>>
>> Best,
>> Daniel
>>
> Look at the log in the temporary directory? Because I often stretch what 
> preview was designed for, I get this kind of problem every now and again 
> and the preview log is nearly always helpful. (It's usually in 
> lyx_tmpbuf0 although with a child document that may not be the case.) 
> Previews are featured near the end of the log. The latex error message 
> usually allows the particular preview causing the problem to be identified.

Thanks. Didn't see your response before.

Okay, I think I found the .log file (lyxpreviewXXXXXX.log).

It says:

---

l.109 \addbibresource
                      {myBib.bib}
The control sequence at the end of the top line
of your error message was never \def'ed. If you have
misspelled it (e.g., `\hobx'), type `I' and the correct
spelling (e.g., `I\hbox'). Otherwise just continue,
and I'll forget about whatever was undefined.

---

However, I am not using any bibliography in that child document. So, 
maybe the previews in the child document fail because of some relation 
to the master (or another child document in the master document)? If I 
disconnect the child from the master (by removing the default master 
document in the Document Settings), the previews work. Isn't it strange 
that the previews would fail because of the master document though 
normally previews are generated based on the child document's preamble? 
(https://www.lyx.org/trac/ticket/9868)

Does the preview fail in a child document whenever it fails in any other 
master/child document of the master?

Or maybe when using a biblatex bibliography in some master/child 
document it affects the previews of all child document? But I wasn't 
able to produce a minimal example yet.

The .tex file (lyxpreviewXXXXXX.tex) contains:

---

\makeatother

\usepackage{babel}
\addbibresource{myBib.bib}

\def\lyxlock{}


\usepackage[active,delayed,showlabels,lyx]{preview}

---

I am not sure how to find out which part of the large document is 
causing the problem.

Daniel