An applet gains focus when loaded, preventing browser keystrokes from working. You can work around this by adding a parameter to the applet tag:
name="initial_focus" value="false"
So far so good. But when the user clicks on the applet even if the applet does not have any user interface controls, then the problem remains.
I guess another way to phrase the question is: How can I get the applet to forward all keystrokes back to the browser?