Dragging clef, bracket, or spacer to score should highlight only target staff, not full system

Ubuntu Studio 14.04, GIT commit: 47b4909

1) new score for >2 instruments
2) drag clef, bracket, or spacer to first measure of staff #2

Result: entire column of measures for the system highlights, even though these items affect only a single staff. Actual drop behavior is correct; just the highlighting is misleading. It's the right highlighting for time and key signatures, barlines, breaks, etc, but wrong for clef, bracket, and spacer.

Borderline minor I guess, but it *is* potentially confusing.