private Dimension getCentralRegionSize() {
		if (centerPanel == null) return super.getSize();
		if (initFinished) return centerPanel.getSize();
		Dimension size = (programFrame == null) ? super.getSize() : programFrame.getSize();
		size.width -= westPanel.getPreferredSize().width;
		size.width -= eastPanel.getPreferredSize().width;
		size.height -= northPanel.getPreferredSize().height;
		size.height -= southPanel.getPreferredSize().height;
		return size;
	}