Please only answer if you are a serious Java programmer or know a lot about computers!?

I'm working on a game using Java3D, and I was wondering why whenever I move my mouse over the applet for a Java3D or JOGL applet, my mouse disappears and reappears very quickly, and when I take the mouse out of the applet, the mouse pointer is fine? And how come games like RuneScape don't do that? Isn't RUneScape made in Java 3D? If you don't know what RuneScape is it's a 3D Java MMORPG made by Jagex Limited. Wouldn't RuneScape either use Java3D or JOGL? The graphics are pretty low tech but they still look good enough. So how come my mouse doesn't get screwed up when I play RuneScape? Thanks.