GtkModelButton is an implementation detail of GTK.
It should not be used by applications. Instead, we
should use menu models to create menus, which are
consistently styled by libadwaita.
While dragging a row in order to reoder the search list, we create
a fake copy of the row that gets dragged into the position where
the user wants the row to be in. This fake row should have its
switch matching the state of its master copy.
Fixes#810
This decouples the user interface parts from the control logic,
making it easy for designers to tweak the look & feel of the rows.
Besides, it makes it easier to introduce Drag & Drop capabilities.
