For standard scroll bars, if the minimum and maximum values are equal, the scroll bar is considered disabled and is hidden. This is the way to temporarily hide a scroll bar when it is not needed for the current contents of the client area.
The SetScrollRange function hides and disables a standard scroll bar when it sets the minimum and maximum values to equal values. No scrolling requests can be made through the scroll bar when it is hidden. SetScrollRange enables the scroll bar and shows it again when it sets the minimum and maximum values to unequal values. The ShowScrollBar function can also be used to hide or show a scroll bar. It does not affect the scroll bar's range or thumb position.