This is the currently selected fill style

This indicator tells you if the selected fill style is currently active. If it is, all new filled entities will use this fill style until it is again changed. It is automatically switched ON whenever a fill style is selected from the Fill Style Name list or the Fill Style list. This indicator cannot be manually switched OFF. However, you can manually switch it ON, causing the selected fill style to become active if it wasn’t previously. Only one fill style can be active at any time, so if your active fill style was on another page (brush patterns, scaleable hatching, bitmap files, or symbol), it will be automatically switched OFF.