Custom Issue Picker

I have created a custom issue picker as a custom field type. I used JIRA source code for it. It works, but I have two questions.

  1. How to hide button Plus, which opens the Issue selector’s dialog?
  2. I need to have a single-issue picker. Although, if I remove multiple tag or set multiple=“false”, it will remain multiple anyway. How to make it single?
<select class="aui-field-issuepicker hidden" name="$" id="$"
data-ajax-options.url="${req.contextPath}/rest/api/1.0/issues/picker""true""true""" >

Would be glad for any help.