code: @Override
  	public boolean isShowing() {
  		if (markedAsVisible) {
  			if (viewPort.getResolution() >= wmsConfig.getMinimumResolution() && viewPort.getResolution() <
  					wmsConfig.getMaximumResolution()) {
  				return true;
  			}
  		}
  		return false;
  	}
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