How to finish or exit preselection

I have been successful in using the preselection notification to draw my own custom graphics, like a highlight or callout for example.  But how do you find out when a preselection is done?  The notification is only fired when an object is preselected and SelectionMgr GetPreSelectedObject always returns null if called outside of this notification.

I can find no way to know when the preselection is finished so that I can turn off my highlight or callout.

Any help would be appreciated.  Thanks.

SolidworksApi macros