I've just revisited the Google Maps widget that's included with the downloadable mortgage calculator project, found on the EDT downloads page.
With the application I had in mind I wanted to plot multiple markers on a map and then have the map automatically centre itself on those markers.
I changed the EGLSource/utils/map/GoogleMap.egl external type to include a reference to the new function and modified the Webcontent/utils/maps/GoogleMap.js to include the new function.
The attached project includes the extended widget plus a sample EGL handler that demonstrates the new feature. The sample adds four markers (four IBM UK offices) to the map and by default the map is positioned to the last marker that was added. There's an 'Auto Center' button that when clicked executes the new autoCenter() function.