At present it does seem as if the map works with an Custom (opensim) grid. I assume this is because it is hardcoded to look to the SL map. If so can this be changed so that it looks at the map for the grid its attached to instead? If this requires the user to specify a custom link to the custom grids map, may I suggest a grid manager function can be added like in Meerkat viewer. A grid manager function would be useful anyway as that way grid specific pointers can be specified once and reused by select the required custom grid from a list. Having to remember all the grid URIs I visit is a real pain. Just like in Meerkat any detailed grid specific information should be added to the Opensim.ini file Grid Section by the grid operator and fetched from the grid itself by the grid manager. This could include a map pointer if one is needed.