Jira Custom Field problems

Hello!
I try to add a new custom field to Jira Issues. And I’ve faced few problems.

  1. JS code of Select2 becomes available and works only by inserting script below in a velocity edit file. $webResourceManager.requireResource("com.atlassian.auiplugin:aui-select2") and other similar methods doesn’t work. Why? How I can fix it?
Script
<script type="text/javascript">
        AJS.toInit(function () {
            AJS.$("#$customField.id").auiSelect2();
        });
    </script>
  1. If I use script above, custom field with Select2 will mostly work correct. But in Issue Screen when I try to add my field by menu “Admin->Add field”, bottom “Submit” will change design and won’t be work. Field will not added. What’s the problem?

My edit velocity file code:

edit.vm
#disable_html_escaping()
#controlHeader ($action $customField.id $customField.name $fieldLayoutItem.required $displayParameters.noHeader)
<form class="aui" style="width: available">
    <script type="text/javascript">
        AJS.toInit(function () {
            AJS.$("#$customField.id").auiSelect2();
        });
    </script>

    <select class="js-example-placeholder-single js-states form-control" name="$customField.id" id="$customField.id" style="width: inherit">
        <option></option>
        #foreach ($option in $options)
            <option value="$option">$option</option>
        #end
    </select>
</form>
#controlFooter ($action $fieldLayoutItem.fieldDescription $displayParameters.noHeader)

My atlassian-plugin.xml web-resource dependencies:

atlassian-plugin.xml
<web-resource key="aui-fields-resources" name="aui-fields Web Resources"> 
    <dependency>com.atlassian.auiplugin:ajs</dependency>
    <dependency>com.atlassian.auiplugin:jquery</dependency>
    <dependency>com.atlassian.auiplugin:jquery-ui-other</dependency>
    <dependency>com.atlassian.auiplugin:aui-select2</dependency>
    <context>atl.general</context>
    <context>atl.admin</context>
    <resource type="download" name="aui-fields.css" location="/css/aui-fields.css"/>  
    <resource type="download" name="aui-fields-js.js" location="/js/aui-fields-js.js"/>
    <resource type="download" name="images/" location="/images"/>  
    <context>aui-fields</context> 
  </web-resource>

Jira v.8.19.1, Atlassian SDK v.8.2.7

I solved both issues.
If somebody have a same problem, you’ll read a text below.

  1. Use this tutorial. Since JIRA 5.0 WebResourceManager is no longer supported.

  2. I removed <form></form> wrapper and the button started working.