code: private Bbox getOverviewMaxBounds() {
  		Bbox targetMaxBounds;
  		if (!useTargetMaxExtent) {
  			targetMaxBounds = new Bbox(getMapModel().getMapInfo().getInitialBounds());
  		} else {
  			// maxBounds was not configured, or need to use maxBounds from target
  			if (targetMap.getMapModel().isInitialized()) {
  				// rely on target map bounds
  				targetMaxBounds = targetMap.getMapModel().getMapView().getMaxBounds();
  			} else {
  				// fall back to configured bounds (should be temporary)
  				targetMaxBounds = new Bbox(targetMap.getMapModel().getMapInfo().getMaxBounds());
  			}
  		}
  		return targetMaxBounds;
  	}
docs: The maximum bounds depend on whether useTargetMaxExtent was set. If not set, the initialBounds from the
  overviewMap are used. It it was set the maximum bounds of the target view is used.
  
  @return maxBounds for overview map