The default TLcdGXYSelectController2 shows a pop-up when a user clicks on a location on the map while keeping the Alt key pressed.

lls gxy controllers selection chooser

This pop-up allows the user to indicate which object or objects must be selected. This is very convenient if there are overlapping objects on the map.

The selection functionality is provided by the applySelection method implementation in TLcdGXYSelectControllerModel2 installed on the TLcdGXYSelectController2.

See the class Javadoc of those classes for an overview of customization options.