Buffer: Cancel buffer without object selected invokes a script error.

[liuar]

1. click Buffer to open the Buffer pane
   

2. click Cance
   

[liuar]

mapName is a local variable defined in function FillLayerList(). If there's no object selected, there will be a error like mapName is undefined in

function OnCancel()
{
    var map = GetParent().Fusion.getMapByName(mapName);
    map.clearSelection();
    //mf.GotoHomePage(); 
}

so, the solution is make the mapName a global variable and check the value of mapName before getting the map.

function OnCancel()
{
    if(mapName == "undefined")
        return;
    
    var map = GetParent().Fusion.getMapByName(mapName);
    map.clearSelection();
    //mf.GotoHomePage();  
}

[liuar]

Fixed at http://trac.osgeo.org/fusion/changeset/2097