How to fix the failed gtk modules when launching a snap?

When launching many snaps, I see the following messages in the terminal:

Gtk-Message: Failed to load module "overlay-scrollbar" 
Gtk-Message: Failed to load module "gail" 
Gtk-Message: Failed to load module "atk-bridge" 
Gtk-Message: Failed to load module "unity-gtk-module"
Gtk-Message: Failed to load module "canberra-gtk-module"

How can I fix the loading of those modules?

The specific snap I'm looking at right now is keepassx-elopio. To install and launch it:

$ sudo snap install keepassx-elopio
$ keepassx-elopio.keepassx

Here is the snapcraft.yaml: https://github.com/ubuntu/snappy-playpen/blob/master/keepassx/snapcraft.yaml