An application sends a ZGM_SETAUTOINCREASESIZE message to set the number of rows that are allocated for the ZeeGrid when it needs to expand to hold more rows.
ZGM_SETAUTOINCREASESIZE
wParam = (WPARAM)(int) iIncreaseSize; //number of rows to increase in memory allocation
lParam = 0; //not used; must be zero
This message does not return a value.