I have a choice column in SharePoint with fill-in choices enabled. I Plumsail I cannot choose from the choices which are added via fill-in. The drop-down in Plumsail only shows the choices entered in the column settings. How can I choose from these "filled-in" choices
yes, you are correct. For Plumsail dropdown and also choice field (enabled fill-in-choices) does not work as you describe.
I would suggest you to do a workaround.
Do a helper list in site content - load these data to a dropdown. When you save the record, check if one of the loaded choices is present in the helper list - if yes - than it is OK.
If the users filled in his own choice, you can create a new item in the helper list and add it to the list.
When the newForm is initialized, you should always prepopulate the dropdown field with the values stored in the helper list
If you need further assistance with the code, I may guide you when I have time.