The current implementation is deficient in many ways, the
worst one being the it relying on GObject semi-synchronous
property emission.
This issue was exposed by the Week view code, where the active
date was updated, but delayed to reach the Week header and some
events were being added ~before~ the active date changed.
With this work, I was also able to figure out a bunch of code
that relied on this (i.e. luck) to work.
When dragging events around, the cursors show a + as opposed to a
an arrow indicating that the event is being moved. This can confuse
users.
The fix is to tell GTK that the drag being performed is a move.
https://bugzilla.gnome.org/show_bug.cgi?id=774922
The Week view exposed a bug where we had different
CSS selectors for the exact same label. This made
them look inconsistent, with different colors and
paddings.
Fix that by ensuring they all use the same style
class. The Year view drawing code needed to be
reworked a little.
https://bugzilla.gnome.org/show_bug.cgi?id=778391
Georges Basile Stavracas Neto