id	summary	reporter	owner	description	type	status	priority	milestone	component	version	resolution	keywords	cc	blockedby	blocking	notify_on_close	platform	project
800	Need undo manager	Conrad Huang		"Instead of global undo for all actions, implement an undo manager that actions can register undo handlers.  For example, the ""cartoon"" command can record the current state before making changes and register an undo handler to reset state.  Code for each action (command or GUI) can decide whether it will support undo."	defect	closed	blocker	Alpha 4	Core		fixed						all	ChimeraX