Updated F27 x86_64 to F28 - Middle mouse button stopped working for "jump to" on scroll track

People, I just upgraded and this problem has manifested on both Chrome and Firefox - ie when there is a long web page, I used to be able to click on the scroll bar track at the top of the page with the middle mouse button, and the page would jump to display from the top of the page - instead of scrolling slowly upwards or by repeatedly clicking on the up arrow on the scroll bar track. Since the problem is in both Chrome and Firefox, I presumed it was some sort of system problem and XFCE seems like the logical place to start? Anyone got any suggestions? Thanks, Phil. -- Philip Rhoades PO Box 896 Cowra NSW 2794 Australia E-mail: phil(a)pricom.com.au