I noticed this issue a while back and came to the conclusion that in order to re-edit the map you would have to take it out of the area of any tabbed panels etc.
I have noticed though that after re-editing following the above that once the map has been altered the js code is moved to the bottom of the page and the option to re-edit the map again is lost.
The only way in order to re-edit the map again is by moving the 2 lines of code back together again.
Like so; "<div id="wagmp_map_1" style="width: 690px; height: 550px;"></div>
What I also find annoying is there is no option to use your own custom icons that are placed on the map. I have to remember to upload them seperately every time.
I really hope there will be an update to this extension as it has opened up many new features for a website.