JInternalFrame Does Not Fully Maximize Under Mac OS X

JInternalFrame f = new JInternalFrame("irc.quakenet.org - #overclockers", true, true, true, true);
	f.setVisible(true);
	f.setSize(300,300);
	f.setEnabled(true);
	f.setMaximizable(true);
	try {
		f.setSelected(true);
	} catch (PropertyVetoException e) {
		e.printStackTrace();
	}