By default, there are two buttons to the far right of the live preview. One to refresh the content, the other to clear out any live changes.

This filter allows you to add, remove, or modify those buttons.

Add additional buttons above the preview pane.

function my_new_preview_button() {

	return '<span class="button button-small button-secondary" title="'.__( 'Some Action', 'my-text-domain' ).'">'.__( 'Some Action', 'my-text-domain' ).'</span>';

add_filter( 'gppro_preview_buttons', 'my_new_preview_button' );