WordPress at a glance
filter is not described

is_active_sidebar filter-hook . WP 3.9.0

Filters whether a dynamic sidebar is considered "active".


add_filter( 'is_active_sidebar', 'filter_function_name_99', 10, 2 );
function filter_function_name_99( $is_active_sidebar, $index ){
	// filter...

	return $is_active_sidebar;
Whether or not the sidebar should be considered "active". In other words, whether the sidebar contains any widgets.
Index, name, or ID of the dynamic sidebar.


Since 3.9.0 Introduced.

Where the hook is called

wp-includes/widgets.php 946
return apply_filters( 'is_active_sidebar', $is_active_sidebar, $index );

Where in WP core the hook is used

wp-includes/class-wp-customize-widgets.php 123
add_filter( 'is_active_sidebar', array( $this, 'tally_sidebars_via_is_active_sidebar_calls' ), 10, 2 );