public void reopenFiles() {
    	ArrayList<File> filesToDisplay = new ArrayList<File>();
    	for(int i=0; i<50; i++) {
    		String key = "display." + Integer.valueOf(i).toString();
    		if (props.containsKey(key)) {
    			String filepath = props.getProperty(key);
    			File file = new File(filepath);
    			if (file.exists()) {
    				filesToDisplay.add(file);
    			}
    		}
    	}
    	
    	if (filesToDisplay.size()>0) {
    		String qStr;
    		if (filesToDisplay.size()==1)
    			qStr = "Reopen one file";
    		else 
    			qStr = "Reopen " + filesToDisplay.size() + " files";
    		Object[] options = {qStr,	"Don't reopen"};
    		int n = JOptionPane.showOptionDialog(this,
    				"Reopen files from last session? ",
    				"Reopen files",
    				JOptionPane.YES_NO_OPTION,
    				JOptionPane.QUESTION_MESSAGE,
    				null,
    				options,
    				options[1]);
    		if (n==0) {
    			for(File file : filesToDisplay) {
    				displayFile(file);
    			}
    		}
    	}
    }