We're using a custom tool very much like the example here: https://examples.unlayer.com/custom_tools/product-library-tool However, when we try to update the rich_text with a value from the selectedProduct , we can see the field being overwritten again with the defaultValue. When I debug the transformer, I can see it being called twice. Once when the product is selected, and another time when it wants to overwrite the rich_text field with the default value. This happens every time I change the product. UNTIL I focus on the rich_text editor (click inside of it). This also only happens with the first custom tool I add. Subsequent tools don't have this issue. And it also seems that when I start selecting products in subsequent tools, the problem goes away.