(NE) Add 'Preview' button (for IPS 4.5 only)

Plugin which will display a 'Preview' button below the editor on the comment form and/or the 'New Topic' form in Forums. This button will invoke the existing preview functionality provided by IPS via a button in the Editor toolbar

Background:

This is the IPS 4.5 compatible version of the following plugin - to 'upgrade', uninstall the older version and then install the newer version.