/// <summary>
/// Changes cell-text in accord with <c><see cref="Undo()">Undo()</see></c> or
/// <c><see cref="Redo()">Redo()</see></c>.
/// </summary>
void RestoreCell()
{
//logfile.Log("UndoRedo.RestoreCell()");
var cell = _it.cell.Clone() as Cell;
int
c = _it.cell.x,
r = _it.cell.y;
_grid[r, c] = cell;
_grid.Colwidth(c, r);
_grid.metricFrozenControls(c);
_grid.ClearSelects(true);
cell.selected = true;
_grid.EnsureDisplayed(cell);
_grid._f.EnableCelleditOperations();
int invalid = YataGrid.INVALID_GRID
| YataGrid.INVALID_FROZ
| YataGrid.INVALID_ROWS;
if (_grid.Propanel != null && _grid.Propanel.Visible)
{
invalid |= YataGrid.INVALID_PROP;
}
_grid.Invalidator(invalid);
}