Don't know of any events for it personality but as an idea of how you could implement it
I'll call your trackbar, trackbar1
1. Somewhere in your main form class declare a variable like:
int LastValue = trackbar1.Value;
2. Double click on the scroll event for the Trackbar and write:
LastValue = trackbar1.Value;
3. Double click on the MouseUp event for the scroll bar. You should add an if statement as shown below to detect if it has actually changed track bar value.
private void trackbar1_MouseUp(object sender, MouseEventArgs e)
{
if(trackbar1.Value != LastValue)
{
}
}