PHP warning: Undefined array key “calendar_size”

Are you using the WP Fullcalendar plugin? If so, add the following code snippet to solve the problem:

add_filter('wpfc_fullcalendar_args', function( $args ) {
    $args['calendar_size'] = "large";
    return $args;
});

You can use the Code Snippets plugin to add this code snippet.

Hi, no just the Events Manager plugin

You could change line 218 of em-calendar.php from this:

if( $args['calendar_size'] === 'large' ) {

To this:

if( array_key_exists( 'calendar_size', $args ) && $args['calendar_size'] === 'large' ) {

And then hope that the plugin owner fixes this in the next release.

Apologies that I missed your second reply last week @joneiseman

I have now tried your fix for those websites that have a responsive calendar view and it has worked – no more PHP warnings every few minutes. Hooray!

If anyone else wants to do this, the relevant em-calendar.php file can be found in the classes folder (there’s one in widgets too).

Thanks very much for your help, I appreciate that.

I wonder how to get the developers to make the fix themselves in the next release…