message: prevent browser scrolling with middle click (FF on win)
diff: @@ -48,6 +48,7 @@ export function getModifiers(event: MouseEvent | Touch): ModifiersKeys {
  export const DefaultInputObserverProps = {
  noScroll: true,
  + noMiddleClickScroll: true,
  noContextMenu: true,
  noPinchZoom: true
  }
  @@ -206,7 +207,7 @@ namespace InputObserver {
  }
  export function fromElement(element: Element, props: InputObserverProps = {}): InputObserver {
  - let { noScroll, noContextMenu, noPinchZoom } = { ...DefaultInputObserverProps, ...props }
  + let { noScroll, noMiddleClickScroll, noContextMenu, noPinchZoom } = { ...DefaultInputObserverProps, ...props }
  let lastTouchDistance = 0
  const pointerDown = Vec2.zero()
  @@ -424,6 +425,9 @@ namespace InputObserver {
  function onMouseDown(ev: MouseEvent) {
  updateModifierKeys(ev)
  buttons = getButtons(ev)
  + if (noMiddleClickScroll && buttons === ButtonsType.Flag.Auxilary) {
  + ev.preventDefault
  + }
  onPointerDown(ev)
  }
  