Well, that what the scroll icons are for
Unfortunately for me they do not always work, as the bottom one does not always appear when it should. It the same problem as with my drop down menu for Actions
Unfortunately again, with Columns it is even worse. Because I am unable to bypass that issue by adding more entries [fake / empty / useless Columns]: no matter how many of the I have, the triangle icon at the bottom shows only if my docked at the top Winamp is in its minimalist form of a thin bar