In releases prior to 3ds Max 4, the MAXScript compiler was treating any undeclared variables used in rollout and plug-in and macroScript handlers as implicitly global.
This was at variance with the use of undeclared variables inside ordinary functions and for-loop bodies and also at variance with the MAXScript documentation.
It was also preventing the new stack-based MAXScript memory management system from achieving maximum effect in handler execution.
All undeclared variables in handler code are now implicitly declared as locals.