Selection tags not updating after save

I have 2 TextInput objects and 1 SelectionTags object, all linked to a dataset.

To modify them, the user must open a LightBox. He can then change the values of these fields and upon closing the LightBox, the new values are copied into the dataset fields and the dataset is saved. When this happens, the TextInput objects update immediately, but the SelectionTags object doesn’t. And for the life of me I can’t figure out why. I tried refreshing the dataset, but no go. Can anyone help?

wixWindow.openLightbox(“Modify”, {
lan: $w(‘#txtLan’).text,
price: $w(‘#txtPrice’).text,
tags: $w(‘#selTags’).options
})
.then( (data) => {
$w(“#dat”).setFieldValue(“Lan”, data.lan);
$w(“#dat”).setFieldValue(“Price”, data.price);
$w(“#dat”).setFieldValue(“Topics”, data.tags);
$w(“#dat”).save()
} );