# Why does the cart add the default variant instead of the selected one?

This usually happens when the **theme’s variant picker is not properly enabled or connected**.

Our app works **on top of Shopify’s native variant configuration**, not independently. This means the theme’s variant picker must be active so Shopify knows which variant is currently selected.

**How to fix this:**

{% stepper %}
{% step %}
**Go to Online Store → Themes → Edit theme**

<figure><img src="/files/AWafGfjc8ZmYrl5jN0x6" alt=""><figcaption></figcaption></figure>
{% endstep %}

{% step %}
**Open the Product template**

<figure><img src="/files/vagzZKrIu4m9QHDH9Ynq" alt=""><figcaption></figcaption></figure>
{% endstep %}

{% step %}
In the **Product information** section:

* Add the **theme’s Variant Picker**
* Add the **OPTIS app block** as well

<figure><img src="/files/0PpzX2E0RvazdmkoZjm9" alt=""><figcaption></figcaption></figure>
{% endstep %}
{% endstepper %}

Once the variant picker is enabled, the selected variant will:

* Stay in sync when customers change variants
* Be correctly added to cart instead of reverting to the default variant

👉 **Important notes**:

* OPTIS **restyles and enhances Shopify variants** - it does **not** create a separate variant system.
* The theme’s variant picker **must remain enabled** for image switching to work properly.
* If you see **both the theme variants and OPTIS swatches showing at the same time**, this is usually a theme conflict. In that case, please **contact our support team** and we’ll help resolve it.

After enabling the variant picker, kindly double-check the product page. If the issue still persists, feel free to reach out - we’re happy to assist further.


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