After creating a simple task and click run, the GDI handle count in Task Manager (CTRL+SHIFT+ESC, "Processes Tab", View->Select Columns..., check "GDI Objects", click OK) hits the Windows XP 10,000 max (per process) in about 45 seconds (seems to go faster if minimized).
May I suggest Cumpuware BoundsChecker or Rational Purify?
-Shaun
PS. Other than that, GREAT program!