gmap module not showing nodes

I have happily set up the gmap module and used it to show users however I just can't get it to work with nodes. These are the questions:

When I enter location while editing a node the map doesn't fill the frame and the +/- arrow keys don't always work.

When I view the node the location block shows a map with the marker in the right place but it's too high a magnification. Where do I change this without hacking the script?

And, crucially, when I look at map/node there is a map but no markers show.

Any help or pointers gratefully accepted.