I am having a problem with the select all feature of the row selectors.

If I chose the select all checkbox in the rowselector-header it selects all of the rows but when I create an alert function to alert the ui.rowKey for each selected row on the page, I get an error. 

Is there any way to hide the select all checkbox in the header of the grid? 

function createGrid(d)

{

$("#sourceInfo").igGrid({

autoGenerateColumns: false,
dataSource: d,
dataSourceType: "json",
primaryKey: "SourceID",
width: "1024px",
height: "500px",
columns: [
{
headerText: "Source Information",
group:
[
{ headerText: "Source ID", key: "SourceID", dataType: "number" },
{ headerText: "Session ID", key: "SessionID", dataType: "number"},
{ headerText: "Source Name", key: "SourceName", dataType: "string" },
{ headerText: "Title", key: "Title", dataType: "string"},
{ headerText: "Source File Name", key: "SourceFileName", dataType: "string" },
{ headerText: "Source Created Date", key: "SourceCreated", dataType: "date", format: "MM/dd/yyyy HH:mm tt" },
{ headerText: "Custodian Name", key: "CustodianName", dataType: "string" },
{ headerText: "Item Total", key: "ItemTotal", dataType: "number"},
{ headerText: "Session Created Date", key: "SessionCreated", dataType: "date", format: "MM/dd/yyyy HH:mm tt" }
]
}],
features: [
{
name: "MultiColumnHeaders"
},
{
name: "Filtering",
type: "local",
mode: "advanced"
},
{
name: 'Paging',
type: "local",
pageSize: 10
},
{
name: 'RowSelectors',
enableCheckBoxes: true,
enableRowNumbering: false,
showCheckBoxesOnFocus: false,
checkBoxStateChanged: function (evt, ui)
{
if (ui.state == "on")
{
selectedSourcesArray.push(ui.rowKey);
}
else
{
selectedSourcesArray = jQuery.grep(selectedSourcesArray, function (value)
{
return value != ui.rowKey;
});
}
}
},
{
name: "Selection",
multipleSelection: true,
}
]
});

}

Also, I've tried to theme just the rowselector section of my grid and I cannot seem to get it to work. I've tried using this code below but not really sure what I should be using in order to make the checkbox smaller in the grid.

.ui-iggrid-rowselector-class
{
font-size:9px!important;
align-content: center;
}