Incompatibility with Custom Sidebars Pro 2.0.9.3 and Events Manager Pro.

We have found an incompatibility with your plugin version 2.0.9.3 and Events Manager Pro. The problem stems from your code in inc/class-custom-sidebars-explain.php and inc/external/wpmu-lib/functions-wpmulib.php, namely:

if ( ! session_id() ) {

session_start();

}

This somehow interferes with the shopping cart function Events Manager Pro. Commenting out the above code fixes the problem and seems to have no adverse effect on using Custom Sidebars Pro

Can you tell me why this code is needed?