The "changed" signal
is emitted when any of the properties other than the
value is altered in a
GtkAdjustment. This happens when the adjustment
object has its values initialised or unset, or when a widget-owned
scrollable object is resized, or when the adjustable widget has a
configure() method and calls it.
Note that a
"value-changed" signal
is also emitted under the same circumstances, regardless of whether
the value itself has been changed.