default value dropdown not showing values on first try

[sleidig]

To Reproduce
Steps to reproduce the behavior:

1. Go to "Admin UI" of Entity Details and edit a field's Default Value config for a configurable-enum field
2. Click on "simple fixed value" mode (filled circle icon)
3. Click on the dropdown to select a value --> it does not give any options
4. (Click on another mode and then again on the fixed mode ... now the field allows to select a dropdown value)

[Abhinegi2]

@sadaf895 also noticed an issue related to this - When we set a default value for any field and save it, it works as expected. but, if we then try to remove the default value by clicking the “Remove default value” icon and save again, the default value is not removed.

Steps to reproduce:

1. add a default value for any field.
2. save the entity configuration; it gets saved as expected.
3. remove the default value using the remove icon and save the entity configuration.
4. Notice that the default value is still present and not removed.