There are two mechanisms in recent versions of wxWidgets which make the
brush list less useful than it once was. Under Windows, scarce resources
-are cleaned up internally if they are not being used. Also, a referencing
+are cleaned up internally if they are not being used. Also, a reference
counting mechanism applied to all GDI objects means that some sharing
of underlying resources is possible. You don't have to keep track of pointers,
-working out when it is safe delete a brush, because the referencing counting does
+working out when it is safe delete a brush, because the reference counting does
it for you. For example, you can set a brush in a device context, and then
immediately delete the brush you passed, because the brush is `copied'.