Steps to reproduce:

1. Go to any content in PlatformUI - notice that URI something like: /ez#/view/<LOCATION>/<LANGUAGE_CODE>
2. Click on "Translations" action button
3. Click on "+ New Translation" - language selection box will show up
4. Click on "Cancel" or cross on top right corner of language selection box to close it
5. Language selection box is being closed but notice that URI has changed to /ez#

Probably cancel handler lacks of preventing default behaviour