Static gtk::STYLE_PROPERTY_BORDER_WIDTH

pub static STYLE_PROPERTY_BORDER_WIDTH: Lazy<&'static str>

A property holding the rendered element’s border width in pixels as a Border. The border is the intermediary spacing property of the padding/border/margin series.

render_frame() uses this property to find out the frame line width, so GtkWidgets rendering frames may need to add up this padding when requesting size