/usr/lib/microb-engine/chrome/toolkit/content/global/platformHTMLBindings.xml change <handler event="keypress" keycode="VK_UP" command="cmd_scrollLineUp" /> to cmd_movePageUp (and same for down)
/usr/lib/microb-engine/chrome/toolkit/content/global/platformHTMLBindings.xml change <handler event="keypress" keycode="VK_UP" command="cmd_scrollLineUp" /> to cmd_movePageUp (and same for down)