wenzelm [Sat, 29 Jun 2013 16:53:19 +0200] rev 52478
manage popup windows via PopupFactory, which prefers light-weight JComponent, but might fall back on JWindow (despite JPanel of 0f88591478e6);
more explicit tooltip hierarchy: manage exactly the visible stack -- caching is part of PopupFactory;
auxiliary geometry measurement via single hidden window;
tuned signature;