Hi,
This sounds like a custom scripted field. I _may_ be able to aid you if you can check what function is executed on the onLoad-event of the PEOPLE form.
To find this, go to the form and click the "Form Properties" button. Under the "Events" tab, there should be a form library listed and one or more functions listed under the onLoad event.
If you can open the listed Library and find the specific function(s) that fire onLoad and paste them here, it could help determine how to structure the Advanced find. If the multi select field is searchable at all.
The supported way of setting up a multi select-ish section is to add a new "Two Options"-field for each TAG you want to be able to select. These can be organized under a form component labelled "Tags"
In other words, create a new component (or whatever the section boxes are called in English) and label it "TAGS". Then, create a new field named "GREEN", specify that it is a "Two Options"-type of field and add it to the TAGS component on the form. If you wish to make it a checkbox, double-click the field once it is placed on the form and select "Checkbox" under the Formatting tab.
Rinse and repeat for all other tags you wish to add, and structure the checkboxes as you see fit on the form.
In order to make the different TAG fields searchable in quick search (Not sure whether you want to do this), go to Settings -> Customizations -> Customize the System and expand the Entities row. Find and expand the PEOPLE entity, and click "Views".
Open the quick search view for the PEOPLE entity and click "Add search columns". Add all the TAG fields to make them searchable without cluttering the search view with lots of columns.
Finally, you can set up the Advanced Find query to search for whichever combination of tags you want. You can for instance search for PEOPLE where BLUE equals value YES and GREEN equals value YES and PURPLE equals value NO.
This way of solving multiple select fields in a supported way may not be a great option if the multi select contains a lot of possible values, or if the multi select lookup has to contain a search field. It is best suited for small-ish picklists, but in return it is fully supported.
Good luck with either option, I will sporadically monitor the question for your feedback.
Regards,
Rasmus
