Magento 2 UiComponent form with tabs has empty fields - forms

Question

I have and issue with empty form fields when I'm using tabs.
If I removing tabs usage, fields contains correct values.
My form uicomponent is large, so I will paste only important parts of configuration:
<argument name="data" xsi:type="array">
<item name="js_config" xsi:type="array">
<item name="provider" xsi:type="string">vendor_modulename_form.vendor_modulename_form_data_source</item>
</item>
<item name="label" xsi:type="string" translate="true">Item</item>
...
</argument>
<settings>
...
<namespace>vendor_modulename_form</namespace>
<dataScope>data</dataScope>
<deps>
<dep>vendor_modulename_form.vendor_modulename_form_data_source</dep>
</deps>
<layout>
<navContainerName>left</navContainerName>
<type>tabs</type>
</layout>
</settings>
<fieldset name="modules">
<settings>
<collapsible>true</collapsible>
<opened>true</opened>
<label translate="true">Details</label>
</settings>
<field name="name" formElement="input">
<argument name="data" xsi:type="array">
<item name="config" xsi:type="array">
<item name="source" xsi:type="string">module</item>
</item>
</argument>
<settings>
<dataType>text</dataType>
<label translate="true">Name</label>
<dataType>text</dataType>
<visible>true</visible>
<dataScope>name</dataScope>
</settings>
</field>
...
</fieldset>
Console log and magento logs are empty. I'm working in developer mode.
Any ideas?

Answer 1

In the dataprovider you have to wrap all the content of your fieldset with the key after loading the data.
Eg:
$id = $this->request->getParam('id');
/** #var Collection $items */
$items = $this->collectionFactory->create()->addFieldToFilter('id', $id)->getItems();
foreach ($items as $item) {
$formData['modules'] = $item->getData();
$this->loadedData[$item->getId()] = $formData;
}