Hi,

Ok, as for my second question, I found a workaround - I used WebDialogWindow. In case it will help someone:

Here is the code of my webdialogwindow. It uses two textfields, one of them is disabled - we want just to show some data from a different column, one is for editing.

Also two labels for signing that textboxes. And one hidden field to store the index of the row in which cell is editing. I didn't add any markup yet for it to look nicer.

<ig:WebDialogWindow ID="wdwMessageBox" runat="server" Height="110px" InitialLocation="Centered"
Width="35%" WindowState="Hidden" DesignTimeMinimize="True" Modal="True">
<ContentPane>
<Template>
<div id="DialogContent" style="text-align: center">
<asp:HiddenField ID="hfRowIndex" runat="server"></asp:HiddenField>
<asp:Label ID="lReadOnly" runat="server" Text="Label">ReadOnlyField:</asp:Label>
<asp:TextBox ID="tbReadOnly" runat="server" Enabled = "False"></asp:TextBox>
<asp:Label ID="lEditing" runat="server" Text="Label">FieldToEdit:</asp:Label>
<asp:TextBox ID="tbEditing" runat="server"></asp:TextBox>
<div id="ErrorDiv" style="text-align: justify; background-color: White; font-size: 12px;
height: 70%">
</div>
<input id="bOk" type="button" value="OK" onclick="return bOk_onclick()" />
<input id="bCancel" type="button" value="Cancel" onclick="return bCancel_onclick()" />
</div>
</Template>
</ContentPane>
<Header CaptionText="Change data">
<MaximizeBox Visible="True" />
</Header>
<Resizer Enabled="True" />
</ig:WebDialogWindow>

And the functions. The first one is handler for EnteringEditMode (can be found in behaviors of webdatagrid). The other two just handlers for clicking buttons in webdialogwindow.

function WebDataGrid1_CellEditing_EnteringEditMode(sender, e) {
///

///Handles imitation of row edit templating by WebDialogWindow
/// var cell = e.getCell();
if (cell.get_column().get_key() == "KeyOfTheColumnYouWantToEdit") {
//hide the rowIndex to retrieve it on clicking OK in the dialog
var rowIndex = cell.get_row().get_index();
var fieldToKeepIndex = document.getElementById('<%= hfrowindex="" clientid="">');
fieldToKeepIndex.value = rowIndex;

//filing some extra field forbidden for editing
var boxReadOnly = document.getElementById('<%= tbreadonly="" clientid="">');
boxReadOnly.value = cell.get_row().get_cellByColumnKey("KeyOfTheColumnYouDoNotWantToEdit").get_value();

//set the value of the textbox inside webdialogwindow from the cell value
var box = document.getElementById('<%= tbediting="" clientid="">');
box.value = cell.get_value();

e.set_cancel(true);

var dialog = $find("<%= wdwmessagebox="" clientid="">");
dialog.show();

}
}

function bOk_onclick() {
//retrieve cell by row index and column key
var fieldToKeepIndex = document.getElementById('<%= hfrowindex="" clientid="">');
var grid = $find("<%= webdatagrid1="" clientid="">");
var row = grid.get_rows().get_row(fieldToKeepIndex.value);
var cell = row.get_cellByColumnKey("KeyOfTheColumnYouWantToEdit");

//retrieve and set value
var box = document.getElementById('<%= tbediting="" clientid="">');
cell.set_value(box.value);

var dialog = $find("<%= wdwmessagebox="" clientid="">");
dialog.hide();
}

function bCancel_onclick() {
var dialog = $find("<%= wdwmessagebox="" clientid="">");
dialog.hide();
}

P.S. Unfortunately formatting is gone after copypasting from VS.