When I drag my score page by means of my mouse pointer in supposedly empty space, which has been my habitual method of getting from A to B in Sib for years, I keep catching a dashed rectangle to the left of the staff, not just singly, but on the same object before every system thru'out the score. This is just as bad as my recurring gripe with invisible empty text frame handles. Every new bug seems engineered to slow down my production time and bring about the Victor Meldrew in me.