The default value of a select field with static options stays when you switch to expression input

[christian-konrad]

Describe the Bug

The default value of a select field with static options stays when you switch to expression input.
This leads to confusing behavior, and to remove the default value, one has to turn back to static values, remove the default, and return to expression input again.

• If the default value isn't part of the expression input options, it is not visible, but still returned as output
• If the default value is part of the expression input options, it is also visible

Steps to Reproduce

1. Add select field, add a static option, and pick it as default
2. Switch input source to expression
3. Add any expression as input
4. --> The default is still in the output data, or even visible if it is represented in the new input options

Bildschirmaufnahme.2023-10-21.um.09.40.39.mov

Expected Behavior

The default value should be cleared when switching to other input sources (expressions or key).

Either no value is preselected (preferred to avoid bias - only when default is set!), or the serialization is fixed

Environment

Form editor in Web Modeler SaaS as of Oct 21 2023

[pinussilvestrus]

As we do not support default values for values key and expressions, we should clean them up once we change the values type - as we already do with other properties.

We could consider adding a modeling behavior for this.