Some expirimentation showed that the drawing window had sized itself to the same dimensions as the timeline window, and was placed exactly under it:
I was able to re-size the window, and everything worked fine. I have not been able to determine what may have led to this behavior; my computer has not shut down while running the program, the program has not terminated abnormally, and no error message has been generated. I have started AS five times today, and the problem has occurred twice.
Software:
Anime Studio Pro version 5.5, build 20060822p.
Operating system:
Windows XP Pro version 2002, SP2
Computer:
Dell Optiplex GX280
Intel Pentium 4, 2.80 GHz
1.0 Gb RAM
ATI Radeon X300/X550 Dual monitor video