The Shadow Brush pane lets you specify the brush type and color of the shadow that you added to a property (e.g., needle marker).
Brush Type — This drop-down list lets you change the brush type of the property.
Brush Color — Depending on which brush type you select, the brush color list will populate with the colors available for that brush type.
Relative Bounds Editor — This pop-up menu displays two bounds editors, Relative Bounds and Relative Clip Bounds, that allows you to determine the size and location of your brush element.