The non-zero default default-border was causing buttons to shrink as
the focus moves around them. Themes which want a default-border should
define it explicitly.
#include "gtkapplicationprivate.h"
#include "gtkactionhelper.h"
-static const GtkBorder default_default_border = { 1, 1, 1, 1 };
+static const GtkBorder default_default_border = { 0, 0, 0, 0 };
static const GtkBorder default_default_outside_border = { 0, 0, 0, 0 };
/* Time out before giving up on getting a key release when animating