Description:
When digitally signing a PDF, clicking "Sign Document..." brings "Select Certificate" window with a list of available certificates on the system. If the list is empty, one obvious reason is a faulty NSS certificate path configuration.

There could be a "fake" certificate line titled "Your certificate is not listed here?" that links to Tools->Options->Security->Certificate Path ("Certificate..." button). This line could be present even if there are available certificates.

Another related small tweak is to put the name "Mozilla" or Firefox somewhere in the security config screen, because it is not obvious at all that a "Certificate..." button would open up a mozilla product profile selection dialog, and NSS relation to Mozilla is also not obvious for non-highly-technical people.

Steps to Reproduce:
1. libreoffice --draw --view some.pdf
2. click "Sign Document" at the top blue notification bar
3. click "Sign Document..." to select a certificate

Actual Results:
"Select Certificate" dialog pops up with list of available certificates (could be empty).

Expected Results:
Hint or link to Tools->Options->Security->Certificate Path to configure the NSS certificate db folder, especially if the list of certificates is empty.


Reproducible: Always


User Profile Reset: No



Additional Info:
Version: 6.4.6.2
Build ID: 6.4.6-3
CPU threads: 8; OS: Linux 5.9; UI render: default; VCL: gtk3; 
Locale: en-US (en_US.UTF-8); UI-Language: en-US
Calc: threaded