protected virtual void OnTreeviewrefCursorChanged(object sender, System.EventArgs e)
{
bool isSelect = treeviewref.Selection.CountSelectedRows() == 1;
editAction1.Sensitive = isSelect && CanEdit;
removeAction1.Sensitive = isSelect && CanDel;
bool SelectFirst = false, SelectLast = false;
bool Filtered = entryFilter.Text != "";
TreeIter iter, SelectIter;
if (treeviewref.Selection.GetSelected(out SelectIter))
{
TreePath SelectPath = RefListStore.GetPath(filter.ConvertIterToChildIter(SelectIter));
RefListStore.GetIterFirst(out iter);
SelectFirst = RefListStore.GetPath(iter).Compare(SelectPath) == 0;
RefListStore.IterNthChild(out iter, RefListStore.IterNChildren() - 1);
SelectLast = RefListStore.GetPath(iter).Compare(SelectPath) == 0;
}
buttonOrdinalUp.Sensitive = isSelect && !Filtered && !SelectFirst;
buttonOrdinalDown.Sensitive = isSelect && !Filtered && !SelectLast;
buttonOk.Sensitive = isSelect;
}