Plz Help---GridView and Cells text

[Shafia]

Hi,
I have a TreeView and a GridView in my UI. On a "CheckChanged" event of
tree, I do the following
GridView1.Rows[nextRow].Cells[0].Text = e.Node.Text;

or rather

((Label)GridView1.Rows[newRow].Cells[0].FindControl("Label5")).Text =
e.Node.Text;

static newRow = 0; and
newRow is incremented on each event call
I need to insert tree node items to the first cells of GridView rows on
subsequent event firing. The problem is when I click a tree node 2nd time

(to set Rows[1].Cells[0].Text) the value from Rows[0].Cells[0].Text
disappears.

What should I do to have it there?

Plz help me,

Shafia