code: public LocationInfo whatIsAtPoint( int pixelX , int pixelY , LocationInfo output ) {
  		if( output == null )
  			output = new LocationInfo();
  
  		int numCategories = confusion.getNumRows();
  
  		synchronized ( this ) {
  			if( pixelX >= gridWidth ) {
  				output.insideMatrix = false;
  				output.col = output.row = pixelY*numCategories/gridHeight;
  			} else {
  				output.insideMatrix = true;
  				output.row = pixelY*numCategories/gridHeight;
  				output.col = pixelX*numCategories/gridWidth;
  			}
  		}
  
  		return output;
  	}
docs: Use to sample the panel to see what is being displayed at the location clicked.  All coordinates
  are in panel coordinates.
  
  @param pixelX x-axis in panel coordinates
  @param pixelY y-axis in panel coordinates
  @param output (Optional) storage for output.
  @return Information on what is at the specified location