The map controls

Hi Guangyan, could you elaborate a bit on your use case? Is this your current mashup? Are you looking to add a such a grid on top of the mashup?

If that's the google maps widget then you can simply create a small mashup containing the UI/info you wish to display on the map.  Then you set the "ToolTipMashupName" in the google map widget properties to point to your new mashup.  Any parameters you define on your mashup will become available to you on the google maps widget so that you can bind parameters and pass values to your mashup to be called by services or just simply displayed.