> winuser.h:#define SM_CYCAPTION 4 Sorry, I was wrong. In the standard Windows Metrics, GetSystemMetrics( SM_CYCAPTION) returns 19. The thumb length equals this value + 2.
infoPtr->uThumblen = GetSystemMetrics( SM_CYCAPTION) + 2; On a native platform, if you modify this value, thumb length will follow this formula. But it is not so simple, there are other conditions for computing the initial thumb length. Stephan
