Topic: version 4 MAXScript Language Improvements /User Interface
A new parameter has been added to spinner UI items, setKeyBrackets, which can be set to true (on) or false (off) to turn on and off the red keyframe brackets that signal a keyframe is present for animated parameters. This allows you to simulate keyframe notification in scripted rollouts by setting this spinner property on or off, most likely in a time change callback function. You can set this as a parameter on a spinner definition,
spinner ... setKeyBrackets:<boolean> ...
or via property assignment,
<spinner>.setKeyBrackets = <boolean>
See also
Rollout User-Interface Controls
Rollout User-Interface Controls Types