code: protected final Boolean isOverlayInstalled(DefaultOverlayable overlayable, JComponent overlay) {
  
          Assert.notNull(overlay, JideOverlayService.OVERLAY);
  
          if (overlayable != null) {
  
              return (overlayable.getOverlayLocation(overlay) != JideOverlayService.NOT_FOUND);
          }
  
          return Boolean.FALSE;
      }
docs: {@inheritDoc}