Thanks, that was helpful.  I'm moving in the same direction of setting individual behaviors on the instance of the child grid and might ask couple of questions withing this post framework later.

While looking into the sample website that you've sent : 

1. Isn't this code suppose to turn on editing of every cell in the childgrid except "id" column..

ColumnEditSetting settings=new ColumnEditSetting();
        settings.ColumnKey="id";
        settings.ReadOnly=true;
        if (childGrid.Behaviors.EditingCore == null)
        {
            childGrid.Behaviors.CreateBehavior<EditingCore>();
        }

        if (childGrid.Behaviors.EditingCore.Behaviors.CellEditing == null)
        {
            childGrid.Behaviors.EditingCore.Behaviors.CreateBehavior<CellEditing>();
        }

        childGrid.Behaviors.EditingCore.Behaviors.CellEditing.ColumnSettings.Add(settings);

Somehow it is not happening when I've run web side. All cells are read only.....

2. Also what property would turn particular cell into read only ( disable) so that different cells within a column could be editable or not . ( Means cells of the same column in different rows)

3. Whould it be that RowIslandDataBinding  a good place to change edit-ability of particular cell...

Thanks

Sorry, actually editing ( #1) works fine, I missed that default trigger is double click... can you just answer 2

& 3 please. Thanks.

Here #4 :

I have pretty much close scenario to your site, EditCore & cell editing turned on on the parent grid and  in the  whdg_RowIslandsPopulating I'm trying to set behavior (cell editing) for the child grid :

ContainerGrid IslandGrid = new ContainerGrid();
            IslandGrid.AutoGenerateColumns = false;
            e.Row.RowIslands.Add(IslandGrid);

            IslandGrid.Behaviors.CreateBehavior<EditingCore>();
            IslandGrid.Behaviors.EditingCore.Behaviors.CreateBehavior<CellEditing>();

At this point I would think that child grid should become editable, but it does not. Parent grid actually editable but the child is not.  I compared with you setting and do not see any difference, although seems like some small piece is missing.  What could cause child grid not to behave as editable after editcore & editcell are added?

I was able to resolve my issues by setting ajaxEnabled to false.

Thank you

I am adding this in the rowIslandsPouplating mehod but I get a script error when the child grid expand.  Runtime Exception: TypeError: $IG[objName] is not a function

My code:

var child = new ContainerGrid();

e.Row.RowIslands.Add(child);

var selection = new RowSelectors

{

Enabled = true,

RowNumbering = false,

RowSelectorCssClass = "selector",

HeaderRowSelectorCssClass = "HeaderRowSelector"

};

child.Behaviors.Add(selection);

selection.RowSelectorClientEvents.RowSelectorClicked = "whdg1_RowSelector_RowSelectorClicked";

child.DataSource = dt;

child.DataBind();

Updating Main Grid.
Maya, I looked at you sample and it does updates the main grid value as expected.
But my scenario is different. I have problem updating main grid right after changes done to child grid in RowUpdating event.  If event triggered by main grid then it is not a problem e.g.      
after line  mr.Amount = 95000;   executed I can see changes on the main grid, if I try to do the same in the child grid section of the same event it’s not working even if I DataBind main grid again. This is the place where   mr.Amount = 35000; got executed.
The issue that I do not know how to address is the following : MainGris get binded on the PageLoad that executed before RowUpdating event, so when value in the master source changed ( mr.Amount = 35000) it could be seen only on the next postback (after any other child grid get expanded).
So somehow if the change occured in main grid and new value assign to underline source (mr.Amount = 95000) then changes can be seen, if event triggered by child grid then changes to main grid ( mr.Amount = 35000) can be seen only after another postback. Can you advise  how to make mr.Amount = 35000 visible without postback.
Project attached
Thanks.