# Topic List Previews (TLP)

**URL:** <https://meta.discourse.org/t/topic-list-previews-tlp/209973>\
**Category:** Theme component\
**Created:** [November 23, 2021, 12:25pm UTC](https://meta.discourse.org/t/topic-list-previews-tlp/209973 "2021-11-23T12:25:59Z")\
**Posts on this page:** 1\
**Showing post:** 545

<div class="post-metadata">

**Author:** ![david](https://sea3.discourse-cdn.com/meta/user_avatar/meta.discourse.org/david/32/157490_2.png) [@david](https://meta.discourse.org/u/david)\
**Post date:** [February 12, 2025, 10:27am UTC](https://meta.discourse.org/t/topic-list-previews-tlp/209973/545 "2025-02-12T10:27:45Z")

</div>

Yup exactly. “Auto” will be the same as “enabled” **if all your installed themes and plugins are compatible with the upgrades**.

If they’re not compatible, then it will act like “disabled”, and a message will be printed to the browser console explaining which theme/plugin needs to be upgraded.

For our official themes/plugins, we’ve made them compatible with both old and new topic-list implementations simultaneously, so that people can upgrade other themes and plugins one-by-one without needing to worry about the site setting. The implementation switch will then happen automatically once the last theme/plugin is ready.

But, ensuring that backwards-compatibility is a lot more work, especially for complex cases. So I can see why it’s been skipped for topic-list-previews 👍

One thing you could do here @robert is add a clear error for people? Something like

```plaintext
import { withSilencedDeprecations } from "discourse/lib/deprecated";

...

withSilencedDeprecations("discourse.hbr-topic-list-overrides", () => {
    api.modifyClass("component:topic-list", {
      init(){
        alert("topic-list-previews cannot be run alongside other themes/plugins which are incompatible with the glimmer topic list. See https://meta.discourse.org/t/209973/521 for details");
        return this._super(...arguments);
      }
    });
  });

```

That will modify the **old** topic list to pop an error if it’s rendered while topic-list-previews is running.

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_[View the full topic](https://meta.discourse.org/t/topic-list-previews-tlp/209973)._