2013-08-27 ago determine completion geometry like tooltip;
2013-08-27 ago explicit "hidden" operation with focus management;
2013-08-27 ago some key event handling in the manner of SideKickBindings, SideKickCompletionPopup;
2013-08-27 ago more systematic JEdit_Lib.key_listener with optional KeyEventWorkaround;
2013-08-13 ago Completion popup based on javax.swing.PopupFactory, which has better cross-platform chances than JWindow (cf. org/gjt/jedit/gui/;