This is the config:-
-Merlin build 63
-Windows 2000
-JaWS1.0.1 - build 18
-Dell Machines optiplex gx110

I have reproduced the problem on two different Win2k machines
Steps to Reproduce
-Launch jaws app manager
-While jaws is busy in fetching remote apps , Navigate through menus
like File-> Preferences -> Java , Advanced etc
- Moving the app manager preference windows also renders the main app manager screen becomes blank
- Though after waiting for some time (long wait ) the GUI returns to normal
Closing the jaws window does not immediately destroys the app manager instead it relinquishes after sometime

Also the tabbed panes are not consistent , they are scattered and not positioned horizontally in one line as usual. They show up in two lines
like Top Line:- Java , Advanced , Certificates
        and then another line --> Genral and Certificated under preference sub menu option

thanks,
Viney Verma