Changes for 2.0.18

• Shapes with a shadow and a Shape.fill value of "transparent" now apply the shadow to the Shape.stroke, instead of the invisible Shape.fill.
• Minor scrollbar fixes.
• Fixed "PanelExpanderButton" click event handler to set InputEvent.handled to true, so that other click event handlers in containing panels will not run.
• Improved the Map constructor and Map.addAll method to accept an instance of Map.

for previous releases, see: https://forum.nwoods.com/t/gojs-version-2-0-17/12682/2