res:dock:: hide system tray icons when display mode is switched.

tower:https://tower.im/projects/1c0cd0c59ef941298c6e6b2ba6833b91/todos/f6b99d2aaaa54cde9722f08c350ce817/#50e2b1ba169b456292ab43198756edd6
Change-Id: I42501c9950f8a8748f99589fbacade5ce3771a6f