select2: Using allowClear with multi-select causes the placeholder to be added as a selection

Prerequisites

• I have searched for similar issues in both open and closed tickets and cannot find a duplicate
• The issue still exists against the latest master branch of Select2
• This is not a usage question (Those should be directed to the community)
• I have attempted to find the simplest possible steps to reproduce the issue
• I have included a failing test as a pull request (Optional)

Steps to reproduce the issue

https://jsfiddle.net/zmtq7an8/

Expected behavior and actual behavior

When I follow those steps, I see…

• The dropdown shows when I click the clear widget.
• The Placeholder option is shown as selected after the process instead.
  I was expecting…
• The clear widget to not drop down the selection area.
• The empty placeholder to not be selected when a new item is selected.

Environment

Browsers

• Google Chrome
• Mozilla Firefox
• Internet Explorer

Operating System

• Windows
• Mac OS X
• Linux
• Mobile

Libraries

• jQuery version: 3.2.1 and 3.1.1
• Select2 version: 4.0.3

Isolating the problem

• This bug happens on the examples page
• The bug happens consistently across all tested browsers
• This bug happens when using Select2 without other plugins
• I can reproduce this bug in a jsbin