You can't scroll up the lister when (un)selecting still exists, when the mouse goes above the first entry in a lister it does not scroll. it always did in the 68k version.
-- Open a lister with a lot of files.
-- Scroll down a 'page' or more.
-- Click and hold on any file and drag the mouse up past the top file.
68k version and the December releases scroll the list to continue selecting files when the mouse is above the top entry.
More of it, our current (svn #1007) 68k version works fine on os4 too in that terms. So its something about os4 build only.