The only way to have a frame with a vertical scrollbar but without a horizontal scrollbar is to define the frame with SCROLLING="auto" (the default), and to have content that does not require horizontal scrolling. There is no way to specify that a frame should have one scrollbar but not the other. Using SCROLLING="yes" will force scrollbars in both directions (even when they aren't needed), and using SCROLLING="no" will inhibit all scrollbars (even when scrolling is necessary to access the frame's content). There are no other values for the SCROLLING attribute.