Inside Macintosh: Mac OS 8 Toolbox Reference /

Chapter 2 - Control Manager Reference / Control Manager Functions

Handling Events in Controls /

TrackControl

NOT RECOMMENDED WITH THE APPEARANCE MANAGER

When the Appearance Manager is available, call HandleControlClick instead of TrackControl to follow the user's cursor movements in a control and provide visual feedback until the user releases the mouse button. HandleControlClick allows modifier keys to be passed in so that the control may use these if the control is set up to handle its own tracking.