private void ProjectTreeView_MouseDown(object sender, MouseEventArgs e)
{
if (e.Button == MouseButtons.Left)
{
var hit = ProjectTreeView.OlvHitTest(e.X, e.Y);
if (hit.Column == olvColumnVisible)
{
FlagManager.Set("PreventSelection");
SelectedItemCache = new List <ProjectTreeNode>();
SelectedItemCache.AddRange(ProjectTreeView.SelectedObjects.OfType <ProjectTreeNode>());
}
}
}