If you hold down the option key during startup, the editor would always reset your preferences. Now there is a cancel button that allows you to abort the operation. Shift-delete now works the same as the forward delete key. The problems with seemingly simple numbers ending with .99999 attached has been virtually erased. The Navigation Services Files dialog can be moved and resized.
Record arrays use brackets instead of parentheses.
File range errors are no longer erroneously reported. Core init routines have been moved into the runtime source code files to allow programmers very low level access during initialization of managers during program startup. Additional calls are now present for the System 8.5 Window Manager. QuickTime and QuickDraw calls were also added.