Hangs with "Insert" > "Comment" then "Insert" > "Hyperlink"

Matthew Paul Thomas, thank you for reporting this and helping make Ubuntu better. This is unreproducible. Please execute the following command, as it will automatically gather debugging information, in a terminal:
apport-collect 1020506

As well, does the program hang indefinitely or does it ultimately crash? What extensions do you have installed? Does any more information exist that would help reproduce the problem?

lsb_release -rd
Description: Ubuntu 12.04 LTS
Release: 12.04

apt-cache policy libreoffice-writer
libreoffice-writer:
  Installed: 1:3.5.3-0ubuntu1
  Candidate: 1:3.5.3-0ubuntu1
  Version table:
 *** 1:3.5.3-0ubuntu1 0
        500 http://us.archive.ubuntu.com/ubuntu/ precise-updates/main i386 Packages
        100 /var/lib/dpkg/status
     1:3.5.2-2ubuntu1 0
        500 http://us.archive.ubuntu.com/ubuntu/ precise/main i386 Packages

[Expired for libreoffice (Ubuntu) because there has been no activity for 60 days.]

Similar problem here. Let me describe it:

1 - I select a text
2 - Click on Insert -> Hyperlink
3 - Begin to type a hyperlink
4 - The URL text box starts responding very slowly to keyboard input, around 1 minute or more per character.

System monitor doesn't show any significant increase in CPU or memory consumption.

Alexis Kauffmann, if you have a bug in Ubuntu, could you please file a new report by executing the following in a terminal:
ubuntu-bug libreoffice

For more on this, please see the Ubuntu Bug Control team and Ubuntu Bug Squad team article:
https://wiki.ubuntu.com/Bugs/BestPractices#X.2BAC8-Reporting.Focus_on_One_Issue

the LibreOffice team article:
https://wiki.ubuntu.com/LibreOfficeBugWrangling

and Ubuntu Community article:
https://help.ubuntu.com/community/ReportingBugs#Bug_reporting_etiquette

When opening up the new report, please feel free to subscribe me to it.

Please note, not filing a new report may delay your problem being addressed as quickly as possible.

Thank you for your understanding.