Calling LayoutChanged does not seem to work in that it does not cause CustomCellDisplayText to be fired.

I have this:

grid.DataSource = new PivotFileDataSource(FileName);
grid.CustomCellDisplayText += Grid_CustomCellDisplayText;

When I display the grid CustomCellDisplayText is called. If I then call grid.LayoutChanged() I'm expecting CustomCellDisplayText to be called again, but it is not and as a result the contents do not get updated.

Any idea what is wrong?