[jacobhulse]

Issue

Cannot activate WooCommerce 2.3.6 and WP Facebook Pixel 2.5 when WordPress Debug Mode is on.

Replication

Enable Debug mode in wp-config.php
Activate either WooCommerce 2.3.6 or WP Facebook Pixel 2.5
Upon activating second plugin, error presents and WordPress halts:
Warning: Cannot modify header information – headers already sent by (output started at …\wp-includes\functions.php:3624) in …\wp-includes\pluggable.php on line 1228

Work Around

Disable Debug mode in wp-config.php
Activate both plugins
Enable Debug mode in wp-config.php

Notes:

Issue does not present when using WooCommerce 2.5