Bug - Filtering hides all subtasks

Hi Aymeric!

Found a small bug :) - Whenever applying filters, and trying to edit a task with many subtasks, subtasks are no longer visible due to the filters. 

Another user had this on the past so maybe its a quick fix:

http://weekplan.userecho.com/topic/294288-subtasks-not-visible-if-filtering-by-role-is-on/