private void checkActiveTileServer() {
    	/* IF POSSIBLE: Make it only check if the tileServer != null
    	 * if that is the case, call checkTileServers and see if it is broken. */
        if (getTileServer() != null && getTileServer().isBroken()) {
            SwingUtilities.invokeLater(new Runnable() {
                public void run() {
                	String error = "The tileserver \"" + getTileServer().getURL() + "\" could not be reached.\r\nMaybe configuring a http-proxy is required.";
                    JOptionPane.showMessageDialog(
                            SwingUtilities.getWindowAncestor(MapPanel.this),
                            error, "TileServer not reachable.", JOptionPane.ERROR_MESSAGE);
                }
            });
        }
    }