Resolve error thrown in Dropdown dismissHandler, issue 278
Resolve error thrown in Dropdown dismissHandler, issue 278

* Fix for issue 278
* `eventTarget[parentNode]` was evaluating to null
* fix prevents this from causing an error when Dropdown's dismissHandler is called by reverting to the version of this assignment from v2.0.19 (before the issue started occuring)

thednp/bootstrap.native,thednp/bootstrap.native,thednp/bootstrap.native