Remove "Speakers" text on homepage

There seems to a title on my homepage at the start of the Speakers widget that says "Speakers". Can you tell me how to remove it?

website: http://sire-htec.org/joust/

Thanks much.

Hello,

It's title of your GK Speakers widget, but I'm not sure why there's no html structure, title should be inside: <h3 class="box-title">
then I would be able to give you css code to hide the title. Did you modify widget source code?

No, I did not change the widget, but the client has decided they don't want that function so I guess that fixed the problem.

Also, I guess the theme does not support nested shortcodes? I was unable to place a button inside a column, so I had to install a separate plugin to handle the columns so I could use the buttons shortcode. Hmmm... at least it works.

Yes, our themes don't support nested shortcode, you can use custom HTML instead one of your shortcode or try to use this plugin:
https://wordpress.org/plugins/nested-shortcodes/

Thanks for the suggestion. I only needed to be able to use the theme's shortcodes within a column, so I am using WEN's Responsive Column Layout Shortcodes to create the columns, then using the theme's shortcodes inside them. Seems to work great.