sevenspark on "[Plugin: Contact Form 7 Dynamic Text Extension] Populating field on contact form popup with title of item in catablog gallery"

Assuming you have a single contact form which is generated on page load, you're going to need a javascript solution (which isn't something this plugin does).

Keep it simple - have a data attribute for each gallery item, when it is clicked, set the value in the contact form via javascript.

Hope that helps,

Chris