mouse : Java Glossary

You don’t see mouse events that happen outside your component. Further, you won’t mouse events on Components like JButton that process MouseEvents and turn them into ActionEvents.

If you want to know what the mouse is doing outside your component, or even outside your application you need to use JDK 1.5 and use the MouseInfo class. To do this in earlier versions, you need to use C++ and JNI, using the Windows

Learning More