Instead of handle_event(), use set_key_capture_widget().
Also, use the fact that we now propagate key events throughout the
stage, and connect to the GtkInspectorPropList instead of the toplevel.
We only want the search bar to be active while that widget is mapped
and able to receive events.
And also, handle the "search bar" visibility on ::search-started.
The code gets rid of the GtkTreeView and replaces it with a GtkListBox.
Most of the logic is now done via GListModel subclasses.
A big change is that this new list is now tracking updates itself and
doesn't need to be manually updated. All code that used to cause rescans
or add forgotten objects to the tree has been removed.
If objects are missing from the object tree, the logic for tracking them
needs to be added.
We can avoid a signal connection per event controller (and the
EventControllerData struct) since every event controller knows the
widget it's attached to.
The sidebar in the object page was using up more space than it deserves.
Replace it with a combo box in the subheader. Now that we have more space,
put the CSS node tree and the style properties in the same page again.
As an implementation detail, the popover hooks the fade out animation
on ::hide. Destroying the popover right away here is not a problem, but
prevents the animation from actually running. ::unmap will be run after
the animation is finished, so destroy the popover there.
When closing the inspector before the main window, we must take
care to sever all signal connections and weak refs, otherwise
things will go bad when the window is closed later.
When closing the application window before closing the inspector window,
the selected widget will be set to NULL once and all the property pages
will try to g_object_weak_unref that NULL widget, so bail out in
gtk_inspector_prop_list_set_object if it's NULL.
https://bugzilla.gnome.org/show_bug.cgi?id=736201
When going from attribute mapping to model, it makes most sense
to go directly to the data tab, and when going from an action
name to the owner, we want to show the actions tab. Make it so.
Move away from cell editing, and use a popover instead. This makes
it easier to e.g. use a color chooser - there's just not enough room
in a cell for many things.
Much of this code is adapted from tests/prop-editor.c.
The entire UI is constructed with templates, so the wrapper
constructors are never called, except for gtk_inspector_window_new,
which gets called from the GTK+ code.
