Disable dragging on alerts / tutorial windows (only the goal window should be draggable)
Make the goal button be always visible

Have it change text to either "Show Goal" or "Hide Goal", depending on whether the goal window is visible or not. Also, simplify the minimize/restore animations (only animate the height and opacity, instead of having it fly around the screen).
If the goal window gets dragged to the right side of the screen, squeeze the main repo visualization a bit to make room.