code: public void onMouseUp(MouseUpEvent event) {
  		// Do not interfere with default behaviour:
  		super.onMouseUp(event);
  
  		// Get the event location in world space:
  		Coordinate worldLocation = getLocation(event, RenderSpace.WORLD);
  
  		// Now execute the GetFeatureInfo for each layer:
  		for (FeatureInfoSupported layer : layers) {
  			GetFeatureInfoFormat f = GetFeatureInfoFormat.fromFormat(format);
  			if (f != null) {
  				switch (f) {
  					case GML2:
  					case GML3:
  					case JSON:
  						if (featureCallback == null) {
  							throw new IllegalStateException(
  									"No callback has been set on the WmsGetFeatureInfoController");
  						}
  						layer.getFeatureInfo(worldLocation, format, featureCallback);
  						break;
  					case HTML:
  					case TEXT:
  					default:
  						if (htmlCallback == null) {
  							throw new IllegalStateException(
  									"No callback has been set on the WmsGetFeatureInfoController");
  						}
  						htmlCallback.onSuccess(layer.getFeatureInfoUrl(worldLocation, format));
  						break;
  
  				}
  			}
  		}
  	}
docs: Execute a GetFeatureInfo on mouse up.