Navigator problems
With any score open, try enabling and then disabling either of the Documents Side By Side or Documents Stacked options under the Display menu. When done, try moving the blue box in the navigator bar with the mouse. It will move, but the display will not change until you click in the score window.
Comments
I see the same thing. Specifically, the box moves, and when you click in the score, the box jumps back to the current view of the score. After that, it works OK. In fact, if you disable the stacked/side option, click in the score, and then drag the box, it's OK.
Also -- probably related -- when you enable side/stack, the box changes to represent the new viewport. But when you disable side/stack, the box is not immediately adjusted. It's as though the navigator is still linked to the now-inactive viewport. And perhaps that's exactly what's happening.
Edward