SftTree/DLL fully supports horizontal scrolling.  With SftTree/DLL, adding a horizontal scroll bar is very easy, even if multiple columns are used. Of course, the tree control window style WS_HSCROLL must be specified when creating the tree control.  By calling RecalcHorizontalExtent, SftTree/DLL will evaluate the optimal horizontal scrolling extent and add a horizontal scroll bar to the control.

Even if a horizontal scroll bar is defined, RecalcHorizontalExtent must be called after all items have been added, otherwise the horizontal scroll bar will not be enabled or updated.