Hi @mvorisek With this PR, Lookup fields always get a clearable icon if they are either nullable or not required. I am of the opinion that

a) clearable should only be activated by default if the field is not required and is nullable at the same time
b) it should still be possible to override this default behaviour using setDropdownOption('clearable', false) - currently not possible as it is forced on rendering.

Furthermore I saw that on a disabled/readOnly field with `multiple = true, the clearable icon was present allowing the erase the dropdown field.

Let me know if you agree, then I can work on a PR to suggest a change.

Hi Michael, "almost always clearable" - what are the usecases? User should be able to revert any chenge he did on the UI side, so after selecting an option it should be always possible to clear it. The validation on send is of course always working.

"multiple" - if there is an issue, PR with testcase highly welcomed!

Hi Michael, "almost always clearable" - what are the usecases? User should be able to revert any chenge he did on the UI side, so after selecting an option it should be always possible to clear it. The validation on send is of course always working.

"multiple" - if there is an issue, PR with testcase highly welcomed!

@mvorisek it's all well as long as you actually use a model to populate the dropdown. In my case I'm not using any models at all in my current project as all DB/data related handling is done through a rest-api. I'm just using atk4 for building the GUI. In that case creating a dropdown using setSource I will not be able to add validation in the model, I could use a check in the callback but as I'm not really interested in what the user chooses, as any value except no value is acceptable. I could use radio-buttons instead but that uses more screen-area than needed to have a minimal and consistent look.

I would prefer to have setDropdownOption('clearable', false) honoured.
I will create a PR for it so you can check if it's ok to implement. (Calling @mkrecek234 for comments as well.)

@rickyosser Fully agree that we should still be able to programmatically configure the clearable setting, independent of the default, model-based logic. There are some use cases where the data structure allows nullable and non-required values, but you want the UI to force the user to choose a value. So needs to be independently configurable for sure.