The BorderImageSource property in the Sandbox.UI.BaseStyles class represents the border-image-source CSS property. It is used to specify the image to be used as the border of an element. This property is of type Sandbox.Texture, which allows you to set a texture as the border image.
To use the BorderImageSource property, assign it a Sandbox.Texture object that represents the image you want to use for the border. This can be useful for creating custom border styles with images.
// Example of setting the BorderImageSource property
var styles = new BaseStyles();
styles.BorderImageSource = Texture.Load("path/to/your/image.png");