For smooth functioning and improved performance we recommend the following:
All Media items like Pen, Brush, etc must be frozen. This is not only to improve rendering performance but also to avoid any exceptions which may arise due to cross-thread references of any unfrozen media object, ArthaChitra being a multi-threaded application. The setters of any base media property by default freezees the object. If the user defines any custom media property he/she must ensure that it is frozen.