[LyX/master] Fix crash after 24926b2e239.

[Richard Kimberly Heck]

On 3/28/20 7:03 PM, Scott Kostyshak wrote:
> On Sat, Mar 28, 2020 at 08:05:04PM +0100, Richard Kimberly Heck wrote:
>> commit 104fdcc9be40df19d50cddad7f8ae9ab63bbf5f7
>> Author: Richard Kimberly Heck <rikiheck at lyx.org>
>> Date:   Sat Mar 28 15:23:13 2020 -0400
>>
>>     Fix crash after 24926b2e239.
>>     
>>     The matched element may not have a parent. I guess the old version of
>>     setExpanded too care of that. Now we have to do so.
>> ---
> Thanks for fixing that, Riki. Did you by chance audit the others of
> 24926b2e239? If not, I will take a look. Note to self: there is also
> a similar change at 273af880.

No, I just ran into that one accidentally. In this case, it's because
the search key can actually match the category headers, like "Document
and Window". I'm not sure that's fully intended, but it is what causes
the crash.

Riki