Vaadin 6 Window weird behaviour

I am trying to open new top level application window with: commons.getMain().getMainWindow().open(new ExternalResource(commons.getMain().getWindow(AdminWindow.NAME) .getURL()), "_blank", true); which will create the window if it doesn’t exists:

public Window getWindow(String name){

Window w = super.getWindow(name);

if (w == null && name.equals(AdminWindow.NAME)){
w = new AdminWindow().createLayout();

return w;

however, from time to time, instead of opening the url to, it will open local ip, 196.168.xx.xx/myserver/admin instead. It doesn’t happen all the time so I am not sure, whether it is a bug or I am doing something wrong

Anyone got the same problem?