Can't get heads up notificiations to work on 6.0.1 (Nexus 5)

[Ketrel]

I'm on a Nexus 5 with Stock 6.0.1 + Magisk + Xposed + GravityBox (used to modify the tiles, power menu, and nav bar only).

I'm trying to get heads up notifications from the following applications: ChompSMS, K9Mail, XiiaLive

All three of the above place and update notifications and the icons show up, but I would like to receive heads up notifications as well.

 

[B. Diddy]

Moved to the Nexus 5 Rooting forum for more specific traffic.

EDIT: Moved back to the main Nexus 5 forum per user request.