System config: x86 server, Solaris 2.6, GeminiPlus H13.

If the user adds a large number of Users/Groups/Machines/Profiles/Platforms,
e.g. 60 Machines, the user wouldn't be able to remove or edit many machines
because the pop-up menu doesn't display them and doesn't have the scrolling
function to scroll to the Machines at the bottom of the list.

Step by step procedure to reproduce this problem:
- startJSD and startJCT.
- click on Machines/Add and create 60 machines.
- click on Machine/Remove.
- click on MAC Address pop-up menu to show the machines added.
  Only 54 machines are shown on my system.