Allow iPad's screen to sleep if the Dropbox app is viewing a file

Currently, the dropbox app for ipad will prevent the ipad sleeping if a document (eg pdf, docx file) is being viewed within the app.

A dropbox engineer has confirmed this is intended behaviour. 

My request is that it should be possible to disable this behaviour, or possibly implement a setting to allow the display sleep to be adjustable when a file is being viewed.  Otherwise the risk of leaving the ipad with the screen forced to stay on is at risk of draining the battery unintentionally.

Of note this is not default behaviour for the android app, which is the way I think it should be.

Thanks

Jon