Dropdown mashup select item and after don't include in the same Dropdown

[tenegabi]

Hello,

I want to select in a dropdown from a list users list ( I have already do this ) , but after add in the second list the user, I want to make sure in the list I can't add second time same user. 

I can do this from Mashup or I need to create a service that compare the users from this two list and create another infotable? 

Thank you in advance. 

[nmutter]

- in mashup you could only add logic to validate same user is not selected. if same user is selected show an error and disable to continue.

- if user should not even be able to get into the state, you need service which creates another infotable without the user.

[tenegabi]

Hello @nmutter ,

1. I don't want to make a program with an error or another steps.
2. That I want to make it now, a service that compare the list of users and after all take the users that is not selected. 

The scope of program is to make fully automatically, not steps for verification.  

[Constantine]

The easiest solution would be to replace your Dropdown + List with a List Shuttle:

It will ensure uniqueness of the users in the right list.

/ Constantine

[nmutter]

uh nice. This widget was not known to me

Might resolve OPs issue