Popup windows are mapped onto the screen directly, without using the window manager. As with the other windows, the constructor for class PopupWindow takes a glyph as its only parameter. Popups are placed at a particular location, as shown in the following snippet.
PopupWindow* popup = new PopupWindow(g); // create a popup from some glyph popup->place( x_location, y_location ); // location to place popup popup->align(0.0, 1.0); // specify alignment, here top left corner popup->map(); // place popup on screen