One of our licensees has reported the following problem:
There is a problem whereby when the appletviewer appears, it
immediately jumps up by about 50 pixels! I have also observed this on our
brand new shiny Solaris box. This is caused by asking the operating system
where it has put the window, and incorrectly subtracting the insets. When
the window is later resized, it is put where Java "thinks" it is.

You might find that the appletviewer won't jump up until you close it in
newer versions of the jdk.