enter (
  GtkEventControllerFocus* self,
  gpointer user_data

Description [src]

Emitted whenever the focus enters into the widget or one of its descendents.

Note that this means you may not get an ::enter signal even though the widget becomes the focus location, in certain cases (such as when the focus moves from a descendent of the widget to the widget itself). If you are interested in these cases, you can monitor the GtkEventControllerFocus:is-focus property for changes.

Default handler:

The default handler is called after the handlers added via g_signal_connect().