docs: private Dimension restoreWindowSize() {
  		Dimension result = null;
  		final String sizestr = preferences.get(prefnzPrefix+PREF_WINDOW_SIZE, null);
  		if (sizestr != null) {
  			int width = 0;
  			int height = 0;
  			final String[] sizes = sizestr.split("[,]");
  			try {
  				width = Integer.parseInt(sizes[0].trim());
  				height = Integer.parseInt(sizes[1].trim());
  			} catch (final Exception e) {
  				// ignoring, cause is prevented by default values;
  			}
  			if (width > 0 && height > 0) {
  				result = new Dimension(width, height);
  				if (logger.isDebugEnabled()) logger.debug("Restoring preference " + PREF_WINDOW_SIZE + "=" + result.width + "," + result.height);
  				this.setSize(result);
  			}
  		}
  		return result;
  	}