This makes the animation feel more stable and keeps the left-most item expanded
when you move the mouse to the left in the tray.
The following behavior details are implemented by this patch:
- we wait to collapse an expanded item till after the tray is hidden if
we are hiding the tray
- we don't collapse an expanded item if the summary notification associated
with it is being shown, unless a different summary item is hovered over
- we don't consider the mouse hovering over a summary notification as
hovering over the tray, which allows us to collapse an expanded summary
item if it is not associated with the summary notification being shown
https://bugzilla.gnome.org/show_bug.cgi?id=636930
5437a3be4b