Title: Plugin Conflicts
Last modified: April 22, 2026

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# Plugin Conflicts

 *  [Sam Wave](https://wordpress.org/support/users/nextwavingit/)
 * (@nextwavingit)
 * [1 month, 2 weeks ago](https://wordpress.org/support/topic/plugin-conflicts-52/)
 * I just wanted to report a couple of plugin conflicts not listed in your documentation.
   Having either of these plugins active at the same time as Smart Slider 3 will
   trigger the following error (php file path shortened by me):
 * `PHP Fatal error: substr_replace(): Cannot use output buffering in output buffering
   display handlers in ./plugins/nextend-smart-slider3-pro/Nextend/Framework/WordPress/
   AssetInjector.php on line 125`
 * For me I only notice this error triggering when I attempt to edit a WooCommerce
   product.
 * Conflicting Plugins:
    - [Hummingbird](https://wpmudev.com/project/wp-hummingbird/) (pro version; page
      caching enabled, asset optimization off)
    - [WP Tax Exemption for WooCommerce](https://wordpress.org/plugins/tax-exemption-woo/)(
      free version, default settings)
 * At the moment I’m setting up a WooCommerce store on an existing site, so I can
   work around the issue by deactivating those plugins while creating/editing products,
   but obviously that’s not a great long-term solution for when the client takes
   over the store.

Viewing 1 replies (of 1 total)

 *  Plugin Support [Gabor](https://wordpress.org/support/users/nextendweb_gabor/)
 * (@nextendweb_gabor)
 * [1 month, 2 weeks ago](https://wordpress.org/support/topic/plugin-conflicts-52/#post-18888037)
 * Hi [@nextwavingit](https://wordpress.org/support/users/nextwavingit/)!
 * Thanks for the information! We will investigate these cases, and if possible,
   we will implement modifications in our code to try to avoid these issues; and
   if that won’t be possible, then we will write down these conflicts in our documentation.

Viewing 1 replies (of 1 total)

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 * ![](https://ps.w.org/smart-slider-3/assets/icon.svg?rev=2307688)
 * [Smart Slider 3](https://wordpress.org/plugins/smart-slider-3/)
 * [Frequently Asked Questions](https://wordpress.org/plugins/smart-slider-3/#faq)
 * [Support Threads](https://wordpress.org/support/plugin/smart-slider-3/)
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 * [Unresolved Topics](https://wordpress.org/support/plugin/smart-slider-3/unresolved/)
 * [Reviews](https://wordpress.org/support/plugin/smart-slider-3/reviews/)

 * 1 reply
 * 2 participants
 * Last reply from: [Gabor](https://wordpress.org/support/users/nextendweb_gabor/)
 * Last activity: [1 month, 2 weeks ago](https://wordpress.org/support/topic/plugin-conflicts-52/#post-18888037)
 * Status: not resolved