- Open a separate mixer instance for the page, so that MM_MIXM_CONTROL_CHANGE notifications can be received.
- Keep line and channel configurations in a global struct.
- Handle MM_MIXM_CONTROL_CHANGE and WM_HSCROLL notifications.
- Increase the height of the trackbar in order to make it fully visible.
- Remove the selection range code.
- Set a range from 0 to 500 and fix the volume calculations accordingly.
- Set a tick frequency of 50 and a page size of 100.
- Play the default sound on TB_ENDTRACK notifications.