TreeDrawer is now centered when opened

Triangle.Compiler/src/main/java/triangle/treeDrawer/DrawerFrame.java

@@ -16,13 +16,20 @@ package triangle.treeDrawer;
 
 import java.awt.Container;
 import java.awt.Dimension;
+import java.awt.Rectangle;
 import java.awt.Toolkit;
+import java.awt.event.AdjustmentEvent;
+import java.awt.event.AdjustmentListener;
+import java.awt.event.ComponentAdapter;
+import java.awt.event.ComponentEvent;
 import java.awt.event.WindowAdapter;
 import java.awt.event.WindowEvent;
 
 import javax.swing.JFrame;
 import javax.swing.JPanel;
+import javax.swing.JScrollBar;
 import javax.swing.JScrollPane;
+import javax.swing.SwingUtilities;
 
 class DrawerFrame extends JFrame {
 	/**
@@ -49,6 +56,19 @@ class DrawerFrame extends JFrame {
 			}
 		});
 		Container contentPane = getContentPane();
-		contentPane.add(new JScrollPane(panel));
+		final JScrollPane jScrollPane = new JScrollPane(panel);
+		
+		contentPane.addComponentListener(new ComponentAdapter() {
+			@Override
+			public void componentResized(ComponentEvent e) {
+				super.componentResized(e);
+				jScrollPane.getHorizontalScrollBar().setValue(jScrollPane.getHorizontalScrollBar().getMaximum());
+				jScrollPane.getHorizontalScrollBar().setValue(jScrollPane.getHorizontalScrollBar().getValue() / 2);
 			}
+		});
+
+		contentPane.add(jScrollPane);
+		
+	}
+
 }