Stroke stroke = new BasicStroke(2.0f);
        plot1.setDomainGridlineStroke(stroke);
        assertFalse(plot1.equals(plot2));
        plot2.setDomainGridlineStroke(stroke);
        assertTrue(plot1.equals(plot2));
        
        // domainGridlinePaint
        plot1.setDomainGridlinePaint(new GradientPaint(1.0f, 2.0f, Color.blue, 
                3.0f, 4.0f, Color.red));
        assertFalse(plot1.equals(plot2));
        plot2.setDomainGridlinePaint(new GradientPaint(1.0f, 2.0f, Color.blue, 
                3.0f, 4.0f, Color.red));
        assertTrue(plot1.equals(plot2));
        
        // rangeGridlinesVisible
        plot1.setRangeGridlinesVisible(false);
        assertFalse(plot1.equals(plot2));
        plot2.setRangeGridlinesVisible(false);
        assertTrue(plot1.equals(plot2));

        // rangeGridlineStroke
        plot1.setRangeGridlineStroke(stroke);
        assertFalse(plot1.equals(plot2));
        plot2.setRangeGridlineStroke(stroke);
        assertTrue(plot1.equals(plot2));
        
        // rangeGridlinePaint
        plot1.setRangeGridlinePaint(new GradientPaint(1.0f, 2.0f, Color.green, 
                3.0f, 4.0f, Color.red));
        assertFalse(plot1.equals(plot2));
        plot2.setRangeGridlinePaint(new GradientPaint(1.0f, 2.0f, Color.green, 
                3.0f, 4.0f, Color.red));
        assertTrue(plot1.equals(plot2));
                
        // rangeZeroBaselineVisible
        plot1.setRangeZeroBaselineVisible(true);
        assertFalse(plot1.equals(plot2));
        plot2.setRangeZeroBaselineVisible(true);
        assertTrue(plot1.equals(plot2));