If a user types text into a GtkEntry on a GtkAssistant page, and then presses Enter to continue to the next page, nothing happens. I suggest that GtkAssistant should designate one appropriate button as its default widget, so that the programmer can use the "activates-default" property of the GtkEntry. I took a look at the source, and it seems that the following steps would need to be taken in gtkassistant.c:

1. In gtk_assistant_init(), the GTK_CAN_DEFAULT flag should be set on any appropriate buttons.
2. In set_assistant_buttons_state() (I think), gtk_window_set_default(GTK_WINDOW(assistant), assistant->whatever_button) should be called on one appropriate button in each configuration. (But only if the programmer hasn't set their own default widget? Not sure how to solve this as there is no gtk_window_get_default()).
3. In compute_last_button_state(), perhaps the Last button should be the default widget if it is visible?

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