How to preset issuelink field with Groovy in Behaviors?

[chaim H]

Current groovy script:

import com.atlassian.jira.component.ComponentAccessor
import com.onresolve.jira.groovy.user.FormField

FormField issuelinks = getFieldById("issuelinks-linktype")
def issuelinksValue = issuelinks.getValue()

issuelinksValue = "dependent (relies) on"

The debug log shows that the value for issuelinks when selecting the option "dependent (relies) on" is "dependent (relies) on".

However, I cannot seem to preset the issuelink field with this script.

It keeps defaulting to the top of the option list in the issuelink field.