We use stock icons and menu items as defined by GTK as far as possible. In this case the icon is GTK_STOCK_NO ("gtk-no"). The icon for breakpoint is a 'red blob' if you use default icon theme for GNOME i.e. clearlooks. The reason we see it as a 'cross' (X) is because of the human (or humanity) icon theme used by Ubuntu.
Debajit,
We use stock icons and menu items as defined by GTK as far as possible. In this case the icon is GTK_STOCK_NO ("gtk-no"). The icon for breakpoint is a 'red blob' if you use default icon theme for GNOME i.e. clearlooks. The reason we see it as a 'cross' (X) is because of the human (or humanity) icon theme used by Ubuntu.