You can edit the generated code or write any script in the upper text area (marker code area)
Clicking [Execute script] runs the script
Try writing e.g. 'map.zoomOut()'
Variable name of the map is creatively 'map'. Markers are arrayed 'marker[pn]' where 'pn' is the point number printed in comments.
[Log] checkbox enables map and marker events, which are displayed on GLog. Marker events are shown for the markers created by the button, not for those loaded from script area (unless you type a listener with GLog.write()).
Listened events can be seen in the end of source code.
Remember that GLog will not open again if it is closed.
With FF1.5 remembering form contents you can reload without losing any data. Bookmarking keeps the location.