This test case illustrates that mouse wheel events are not properly
delivered to Java applets on Mac OS X. Configure Java so that the Java
Console is enabled. Open this web page (and the associated applet) on
a machine with a mouse that has a scroll wheel. Click the middle of
the window the applet opens outside the web browser. Rotate the scroll
wheel. Note from the Java Console output that scroll wheel events are
delivered. Now click the blue area in the web page corresponding to
the applet and rotate the mouse wheel. Note that no mouse wheel events
are delivered. On both Windows and X11 (Linux, Solaris) platforms,
mouse wheel events are delivered properly to the applet.

<P>

Note that this issue is not focus related. Again click the center of
the applet's external window. Type a few keys. Note that the key press
events are picked up and that the focus is on the canvas inside the
external window. Now click the blue box in the browser page
corresponding to the applet. Type a few keys. The applet clearly has
the focus, but the web browser is still intercepting the mouse wheel
events. If you shrink the web browser window until the vertical
scrollbar shows up, and then click in the region of the web page
outside the applet, note that the scroll wheel controls the vertical
scrollbar of the browser. Now click in the applet so it has the
focus. The scroll wheel still controls the web browser's scrollbar
instead of sending the events to the applet. On Windows and X11
platforms, when an applet has the focus, it captures the scroll wheel
events.

<P>

It could be argued that the current Mac OS X behavior is correct, but
the fact is that there are applets for which the scroll wheel is the
best mode of interaction, and it would be best to have consistent
behavior across platforms.

<P>

<applet code="MouseWheelApplet"
     width=256
     height=256
     codebase="."
     archive="MouseWheelApplet.class">
</applet>