Concatenation Rule - Improve column selection

## Background [Optional]
Currently when selecting the attributes to be concatenated, user has to click on radio dials, then it adds the field, and user has to then open the selection again and choose the field by clicking on the radio button.

## Question
Is it possible to show all fields with check-boxes, and the user can then just tick the fields which are to be used and the order of selection should be the order of concatenation, instead of the radio dial?