There’s a bug in the maps API that can cause the infoWindow to size incorrectly. Please ‘star’ the issue with Google here:
I implemented a workaround in MapPress 2.41+, but I’m not sure it works in all cases. Please provide a URL.
For the outer scrollbars, here’s some things to try:
1. Install the latest MapPress
2. Use a bigger (taller) map
3. In the infowindow CSS, give Google a hint that you want the infowindow wider, for example ‘min-width:500px’
4. Use the MapPress ‘infobox’ style instead of the standard infowindows (the infobox sizes correctly).
Google only applies the outer scrollbars. The inner scrollbars may be coming from the infowindow content. Is the CSS ‘overflow:auto’ applied somewhere in the content of the infoWindow? You can use Firebug or Chrome/IE Developer Tools to check.