public Rectangle GetCellBounds(TreePosition pos, CellView cell, bool includeMargin)
{
var col = GetCellColumn (cell);
var cr = GetCellRenderer (cell);
Gtk.TreeIter iter = ((IterPos)pos).Iter;
var rect = includeMargin ? ((ICellRendererTarget)this).GetCellBackgroundBounds (col, cr, iter) : ((ICellRendererTarget)this).GetCellBounds (col, cr, iter);
return rect;
}